Archive for the ‘Java’ Category:

Scanner Java: What is Scanner Class In Java?

On the surface, the question what is a scanner class in Java seems easy. A scanner class is a class in Java that allows the program to see user input. However, for the beginning programmer, this information may not be enough. Therefore, this article will examine the subject in depth.

What is Java: An Introduction to the Language

While Java has been around for a while, some history may be in order to understand exactly what a scanner class in Java entails.  After all, without an understanding of the language, the coder may not realize how crucial the scanner class is to Java programming, and may completely overlook the class's utility.

Java was originally developed by James Gosling in 1991 for use in one of his projects. Interestingly, the language was originally known as “Oak” due to a tree that lived outside of Gosling's office.

After going through iterations such as “woods”, the name “Java” was chosen at random from a list of words. The name “Java” was not planned in the slightest.  Tutorialspoint offers an interesting history of Java.

Incidentally, the JavaScript programming language only shares certain features with Java. The two programming languages are not related and confusion between the two can be costly. Code written in Java will not run in a JavaScript environment and vice-versa.

Ultimately, the Java programming language was released in 1995 by Sun Microsystems and became extremely popular for a number of reasons.

First of all, Java is platform independent, meaning that the Java Virtual Machine interprets the code on which ever machine it runs on. Java does not need a separately compiled version of a program for each computer it needs to run on to function properly.

The error checking is also robust, unlike some other popular languages, and Java also supports multi-threading, which almost all modern computers can use to speed processing.

Also, Java is mostly open-source, with much of the source code being released to the general public by Sun in 2006. So, any proficient coder can look at the source code and optimize it or alter it.

Certain other languages, on the other hand, may only be altered by their respective owners, slowing down innovation and creating bottlenecks.

However, possibly the most salient reason for Java's success is that it implements object-oriented programming, which is an increasingly popular category of language among coders and is crucial to understanding the concept of a scanner class in Java.


Why and How Java Uses Classes

As noted above, Java is an object-oriented language. This means that snippets of code are given attributes and treated as objects would be in the physical world.

For example, in the real world, a bicycle may have two wheels, be red and have a horn. In the coding world, these attributes would be represented by classes.

As is always the case with a programming language, objects and classes have a specific naming convention which must be followed.

Generally, in Java, the naming convention is object.class. Please note that other programming languages also follow this convention, most notably JavaScript.

But why do programming languages bother with this? The computer doesn't care about objects or classes, so why would a language bother with being object-based? 

Well, the computer may not care, but humans are intrinsic tool-users, so we are used to dealing with objects every day. So, object-oriented programming is an attempt to make programming more natural for humans.

Although object-oriented programming may not seem natural for most people, compared to languages like FORTRAN or COBOL, object-oriented languages are easier to learn.

So now the coder understands a major reason as to Java came to become one of the most popular languages in the world.

The coder should also understand what a class is, and how objects in Java use object-oriented programming in order to make coding concepts easier for coders.


The Scanner Class in Java: A Special Case

However, the scanner class is particular to Java, and the concept should be fully explained. The scanner class is part of the Java util package, which is also important to understand.

The Java util package contains a number of classes that are crucial to effectively working with Java. As always, the naming convention is object.package.class. So when using the util package, the proper nomenclature would be object.util.class. 

While this article is concerned with remaining simple, coders who wish to find a more complex definition of scanner class in Java would be advised to visit geeksforgeeks.org

The first, and perhaps most important class is “arrays”. This class allows the Java user to search and sort arrays.

Arrays are often used in programming languages—they essentially are lists of variables that store information, including letters, numbers and even other arrays. Being able to search and sort through arrays is crucial, and this util class allows coders to do just that.

There are many other util classes which are important to all levels of coding. 

They include the Dictionary class, which helps map keyboard presses to values, the EventListenerProxy which can aid in getting input from users, and the EventObject class, which helps the coder make something happen onscreen when something else occurs.

However, almost unarguably, the most important class contained in the util package is the scanner class. The scanner class is a simple text parser that allows a program written in Java to “see” primitive types and strings.

In other words, this class allows an object to react to what a user types after the user inputs a string.

This class offers the easiest way for a beginning programmer to add interactivity to their coding.

It is often used, even when there are other alternatives available, due to its utility. However, there are some situations in which another class may be more appropriate.

For example, the scanner class should be avoided when creating an application needing fast input response, such as a game. The class has a slow response time and therefore gaming would not be appropriate.

However, for most other uses, the scanner class excels. General text input is handled very well by this class, and so text input for databases, spreadsheets and other programs is often given to this class in Java.

It's difficult to envision the Java environment being as easy-to-use and successful as it is without the usage of scanner class.


A Sample of Methods for the Scanner Class in Java

Of course, like almost any class, the Scanner class has methods which help define what the scanner is doing at that particular moment. A few of those methods are as follows:

The method listed as close() voids the scanner completely. This method stops whatever the scanner is doing and closes it. This method is obviously useful when the coder wishes for the scanner to completely cease functioning.

Meanwhile, the method listed as FindInLine() is used to find the next sequence constructed from the specified string, ignoring delimiters.

The final example is hasNextBoolean() which looks to see if the text response is a yes or no answer and then respond accordingly. As with all Boolean functions, only yes or no answers are accepted with this method, which is useful in certain situations.

If the reader is interested in a more comprehensive list of methods for the scanner class in Java, Javatpoint has an extensive list, and is highly recommended.


Effectively Using The Scanner Class In Java

As can be seen from the above examples, the scanner class is flexible and useful. However, like most programming tools, there are situations in which the use should be avoided.

For example, if the coder is attempting to create a multithreaded program, choosing to use the Java Scanner class should be avoided unless external synchronization is used. 

However, this is no reason to avoid the scanner class in Java. While exceptions do exist, this class is one of the most used in all of Java, and with good reason.

When a coder needs a simple, reliable class for receiving text input from a user, the scanner class should be considered. The prepared coder should be familiar with the scanner class and use it today.

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What Is The JavaScript ParseInt Function?

JavaScript is a powerful programming language that thrives on the web. It comes with a number of functions that make programming websites and web application simple. A useful function Javascript provides is the parseInt() function.

The JavaScript parseInt() function parses a string and returns an integer value. This function is useful for times where you want to convert data a user has inputted as a string to an integer. The applications for parseInt() are numerous, and it will become a valuable tool in your programming toolset.

We will walk you through how the parseInt() function works, practical applications of the function, technical information, and some common mistakes programmers make when using the parseInt() function.

How To Use The JavaScript ParseInt() Function

In order to explain what the parseInt() function is, and how it works, we will break up the information into the following sections:

  • Overview
  • Constructor
  • Use
  • Examples
  • Return values

Overview

The parseInt() function parses a string and either returns a number, or NaN(Not a number) if the string read in does not contain a valid number. In a perfect world, you would only deal with solid numbers that can easily be converted into integers, like 10, or 500.

However, you may find times where there are numbers that you want to convert to a string that are represented as hexadecimal numbers. Hexadecimals aren’t the only numbers you have to concern yourself with, there are also octals and other number bases that you may need to convert.

Thankfully, the parseInt() function is versatile and accepts parameters that specifically help programmers convert strings to numbers based on radix. This is important work done by the constructor of the parseInt() function.

Constructor

The parseInt() function takes the following parameters:

  • String
  • Radix

The String you want to parse is a required parameter in this function.

The radix parameter is an optional parameter that specifies what numeral system needs to be used for the conversion process. If you were to input a radix of 16, the parseInt() function would interpret the number you are parsing from the string as a hexadecimal.

The radix parameter can be any value in between 2 and 36. Because the radix parameter can be omitted, it is important to know what default value is used. When there is no radix parameter defined there are a few assumptions JavaScript makes to interpret the string.

If the string begins with “0x” then the radix interpretation will be 16. Otherwise, any other value provided to the parseInt() function will be interpreted with the radix of 10. It is important to know this going into using the parseInt() function in case you run into miscalculations of integers you want to parse.

When you start using the parseInt() function, it is important that you get in the habit of defining your radix. This is especially true if you are working with large data sets that have the possibility to deviate. Creating a function that shifts the radix based on expected number value in a string is well worth your time.

Use

Because JavaScript parseInt() is a function, you usually want to set it to a variable. This way you can store the integer value returned by the function. Common usage of the parseInt() function is as follows: var a = parseInt(“10”);

Examples

The parseInt() function can convert many different string values to integers. Regular numbers, octals, and hexadecimals are among some of the most common conversions used with the parseInt() function. The following examples are common uses of parseInt():

  • parseInt(“10”) returns 10
  • parseInt(“010”) returns 10
  • parseInt(“17”, 8) returns 15
  • parseInt(“C”, 16) returns 12
  • parseInt(“-0XC”, 16) returns -12

Notice that if you define the radix value as 16, you can use characters that are not numerals without throwing a NaN error.

Return Values

When the parseInt() function is used correctly it returns an integer. However, there will be times when the parseInt() function cannot correctly parse a string, in those cases, it will return a NaN error.

It is important that you pay attention to the return value provided to you by parseInt() and create an exception that handles the NaN error.

If the first character in the string cannot be converted to a number, then the Javascript parseInt() function will throw a NaN error. Likewise, if you supply an empty string, the parseInt() function will return nothing.

Applications Of Javascript ParseInt Function

The parseInt() function is a powerful tool that has a number of practical applications. The following applications of the parseInt() function demonstrate its practicality:

  • Sanitize user inputs
  • Convert octal and hexadecimal values
  • Format Microsoft JSON Date

Sanitize User Inputs

The primary application of parseInt() is to sanitize user inputs. There may be moments where you have users input text into a text box. Any time the user inputs text into a text box, that value will be referred to as a string.

In order to pull the integer value you desire from the string, you must use the JavaScript parseInt() function. Getting comfortable with this function will better prepare you to deal with a common interaction paradigm on the web.

Convert Octal And Hexadecimal Values

Javascript’s parseInt() function isn’t just useful for sanitizing user inputs, it is also useful as a conversion tool. There may be times where you are given hexadecimal or octal values as strings. No one wants to have to look up a key every time they see one of these values.

Unless you have octal or hexadecimal values memorized, or you understand the conversion, the parseInt() function can do much of the heavy lifting in converting those values into human readable integers. You might be creating a website component that relies on strictly integer values. The best way to interpret those values would be to use the parseInt() function.

Format Microsoft JSON Date

Another key practical application of parseInt() is for use as a date converter. There will be times where you have to format Date information to make more human-readable text. In a popular example on StackOverflow with over 674,333 views a user explains how to use the parseInt() function to sanitize date data.

Notice that in most examples parseInt() is used to make information more readable. Practical applications of the parseInt() function generally make the use of other functions easier. Knowledge of regular expressions will help you better use of this function.

Technical Information

an open book about javascript programming

Image Source: Unsplash.com

 

The JavaScript parseInt() function is usable on all modern web browsers. Basic support is available for all web browser platforms, and each browser supports parsing leading zero strings.

This function also has 3 specifications that can easily be read for more technical information on the parseInt() function. The following specifications exist for parseInt():

  • ECMAScript 1st Edition
  • ECMAScript 5.1
  • ECMAScript 2015
  • ECMAScript Latest Draft

Another technical case that is important to understand is how different versions of ECMAScript numeric strings with leading zeroes that do not have defined radixes. ECMAScript3 discourages the use of parsing octals with no radix defined. In ECMAScript 5, parsing an octal without defining the radix as 8 will definitely not work. It is important that you always define your radix when using the parseInt() function on octal and hexadecimal values.

Common Mistakes

One of the most common mistakes programmers make when using JavaScript parseInt() , is not setting their radix. A user may parse a string that has a leading zero and receive output that is different from what they are expecting. This Stack Overflow statistic demonstrates that this is a common error with over 14,880 views over 7 years.

To solve this mistake, it is imperative that you understand how parseInt() parses strings when no radix is supplied. Always supply a radix, it is better to be explicit when using the parseInt() function.

The ParseInt() Function Is A Necessary JavaScript Tool

Javascript’s parseInt() function can be used in a number of instances to make JavaScript development easier. Common uses of this function involve parsing strings to convert numbers into an Integer format that can easily be manipulated.

It is important that you remember to define the radix. If you don’t define your radix you could run into issues using the parseInt() function that can slow down your development time. As always, consult StackOverflow or Quora if you run into bugs that you cannot fix on your own!

 

Featured Image Source: Pixabay.com

The Top 21 Most Common Java Interview Questions

It pays to know of the one most popular programming languages.

In 2016, Oracle noted Java was used by approximately 9 million developers and running on 7 billion devices worldwide. That’s an exponential growth curve, considering it’s only been public for less than 25 years.

Java was born in Santa Clara, California as part of the Silicon Valley boom in the early 1990s. Java was developed at Sun Microsystems to boost the abilities and effectiveness of C++ language.

It was released to the public in 1995 and quickly gained popularity. Java was designed to run independent of platform. Any device that has Java Runtime Environment (JRE), a lightweight application, can run a Java program. This provided developers a “write once, run anywhere” programming language. It significantly reduced the coding and resources necessary to write a program for multiple platforms.

Java was eventually acquired by Oracle as part of its larger purchase of Sun in January 2010.

Of all the programming languages available, how did Java surpass them and become such a hot commodity in today’s job market?


Why Java is One of the Top Programming Languages

Java is undeniably popular. It consistently leads the TIOBE index – a measure of the popularity of programming languages created by the TIOBE Company in the Netherlands – with the most recent rating of 17.8%. That’s up 5.4% from last year.

Below are just a few of the reasons why Java has become so popular:

  • The Five Principles: Sun Microsystems wanted to build on the C++ language and create something that more people could use. They explained this goal as Five Principles which guided the initial design and subsequent iterations of the language.
  • Open Source: Anyone can create Java applications at no cost. A massive community of users has grown around Java, providing additional resources and expertise for developers. Message boards and forums provide free publicity and ongoing training for users. With a growing library of functions and classes, Java is an easy choice when looking to deliver results quickly.
  • Concurrent: Programmers can process data in parallel, meaning multiple programs can run at the same time.This increases the efficiency and power of programs written in Java.
  • Wide Range of Uses: Java is used in banking and financial services, IT, and stock market trades. It provides a solid foundation for websites. Java is critical for applications in a wide range of industries.
  • Big-Name Users: Companies and programs that use Java include Minecraft, Adobe Creative, Google, and more.

Thanks to the high demand for this skill set, average salary range has been reported at $93,570 for a Java programmer. It’s no wonder Java developers and programmers are in such demand.

Knowing Java is only part of what you need to earn a position with one of the top companies in the world. Let’s look closely at the interview process and the questions you can expect.



Interview Questions

The interview is designed to give the business a better understanding of who you will be as an employee and how you will work as part of a team. The questions will also cover specific technical skills you’ll need.

Problem-Solving Questions

Managers want problem solvers in every layer of employment – from entry level to top management. The hiring manager will test your personal skills by asking about missed deadlines, office conflicts, loss of data, and overlapping deadlines. They are not only looking to see that you know how to fix a problem but want to know how you can deliver solutions when problems occur.

Below are a few of the questions you should prepare to answer:

question mark
  • What is a challenge you’ve faced in the past and how did you handle it?
  • Have you ever had a project that was behind schedule? How did you manage the work and meet the deadline?
  • Tell me about a time where you faced a problem you couldn’t solve. How did you handle it?
  • Describe a creative solution you used to handle a work-related problem?
  • What kind of troubleshooting process do you use in your work?

Leadership-Based Questions

Do you wait for a solution or do you lead by proactively finding the answer? Everyone has their comfort zone with leadership. Hiring managers want to know where you will fit within the company. They may ask questions about your proudest accomplishment, what do you want to gain from this job, or if would you speak up if you knew something in the process was wrong.

  • In your opinion, what makes a great leader?
  • What experience do you have that will help you in this position?
  • What work-related responsibilities have you had in the past?
  • If you knew a manager was wrong, how would you handle it?
  • What is your greatest strength and greatest weakness?


Java Interview Questions

Java is considered one of the easier programming languages, especially when compared to languages like C, C++, Fortran, and Pascal. Even so, there are core skills and expertise every developer and programmer working in Java should have mastered.

man having an interview

Source: Freepik.com

The technical questions in the interview will be designed to not only determine your comfort and competence in Java programming, but also check that you have the core skills for the position. Before the interview, make sure to review the job listing to identify what those skills are. Take time to brush up on those skills and have answers ready for any specific technical questions the interviewer might ask.

Let’s look at a few other common Java interview questions:

  • Can you explain what a “platform independent programming language” means, and why Java fits this description?
  • Can you explain the difference between StringBuffer and String?
  • Tell me what you know about the finalize() method?
  • Can you explain the difference in Set and List interface?
  • Why doesn’t Java support multiple inheritances?
  • Tell me what you know about Java Exception Handling? Is there a difference between “throw” and “throws”?
  • What is the Final keyword in Java? How is a super keyword used?
  • Can you explain the abstract class in Java? How is it different from an abstract class in C++?
  • How does static variable work in Java?
  • How does Java store objects in memory?
  • What are the differences between HashTable and HashMap in Java?

Keep in mind, these are common Java interview questions. Many jobs will require specialized technical knowledge and Java programming that isn’t covered by these questions. Understand the position you are interviewing for and the expectations for the job.

Next, we’ll go over a few other things you can do to ace your interview.


Appearances Mean Everything

Beyond knowing the answers to the top interview questions, landing the job is all about first impressions and professionalism. Employers are looking for Java programmers that fit within the corporate culture and take pride in themselves. Confidence in your abilities translates to confidence in your appearance and mannerisms.

man holding laptop

Below are some guidelines to acing the first impression:

Prepare for the Interview

You are an expert in your field, Java programming, but companies also expect you to know about them and how they are using Java. Go beyond the simple Google search and see what the company says about itself. Look at what others are saying about the company and who are their competitors. Review their business pain points and prepare responses on how you can solve them.

Dress Appropriately

Sometimes a recruiter or the hiring manager will provide guidelines on what to wear. If they don’t, do your research and learn what is expected in the corporate culture. Not every company will expect a suit, but some won’t give you a second glance if you wear jeans. In general, interviews tend to be more formal than your daily wear once you land the job.

  • Here are recommendations for women, including what to wear and suggestions on where to buy layers, blazers, dresses, and pants. You don’t have to buy the exact item in the article; use it as a guideline and tailor it to your style and budget.
  • Likewise, there are also suggestions for men for ties, shirts, and trousers. Again, make the style your own, but make sure it fits the expectations.

Print your Resume

Some companies and human resource departments still prefer paper. Print and bring a copy of your resume. It’s better to have it and not need it, then to not be prepared for someone to review your resume.

Accessories

Store your printed resume, laptop and any samples in a portfolio or briefcase, so they are crisp when you arrive. You will lose credibility if your work looks sloppy.

Follow Up

Gather business cards or contact information during the interview. Email a thank-you note within 24 hours (the sooner the better) of the interview. Express not only your thanks, but also your excitement and recap what you can bring to the company.


A Final Word on Java Interview Questions

Learning Java is only the first step in a career. Even as the demand for quality employees and the sheer number of companies using Java continues to rise, competition for jobs is still fierce.

Preparing for Java interview questions and doing your research before you meet with a recruiter is critical to landing the job you want. You may be the best Java programmer for a position, but if you can’t ace the interview and show what an asset you will be for the company, you may never get a chance to show what you can do.

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Everything You Need to Know About Arraylist Java

Java programmers and developers are in demand.

With more than 7 billion devices using Java across the world, companies are looking for Java programmers. Even with more than 9 million Java developers, demand is high for new talent.

There is a good reason why Java is so popular with developers and businesses. Java eliminates many of the “quirks” and constructs that plague other languages. This makes it much easier to learn. Java is also an object-oriented language, supporting collaborating objects in a program. Java is distributed, so it supports network connectivity with TCP/IP support in Java class libraries. This lets an application written in Java open and access remote objects across the Internet.

One powerful feature of Java is the arraylist Java, or dynamic arrays that make it easier to input and use a collection of elements in Java. We’re going to take a closer look at arraylists in Java, an important feature in the language, and how they can be used.

Ready to go? Let’s get started…


A Little Background in Java

Java was built by a small group of engineers led by James Gosling at Sun Microsystems in 1992. The original goal of Java seemed simple – correct a few of the problems and inefficiencies in C and C++.

A core focus of the Java design was to have as few implementation dependencies as possible. This meant that Java code could run on all platforms that support Java without needing to be recompiled. Developers could write the code once and it could run independent of platform – or “write once, run anywhere” as it has since become known.

To keep Java programs portable, and able to run similarly on almost any combination of operating system or hardware, Java code is compiled into Java bytecode instead of an architecture -specific machine code. Java bytecode can then be executed by a Java virtual machine written for the host hardware and installed on the machine.

This ingenious design allows Java to be run on almost any machine or platform, saving programmers and developers time and effort when they are writing code for different platforms.

Where is Java Programming Used?

Over time, many businesses and programmers have taken advantage of the platform-independent power of Java.

Java is the basis for networked applications and a global standard for developing and creating embedded applications. It is the core of web content, games, and enterprise
applications.

Java is the foundation of apps in Android. The insurance industry, education groups, and healthcare organizations all use applications running on Java. Even government facilities and the department of defense rely on Java and Java applications.

Java programming is used in many different devices, including laptops and computers, smartphones, gaming consoles, medical devices, and navigation systems. Java is also a critical tool for websites. Java can be used to create programs, known as applets, that can be embedded in web pages. Applets create the interactive widgets and tools, like maps and games, found on many web pages.

Now that we have a little background into Java, let’s dig into what an arraylist Java is and how they are used.


What is Arraylist Java?

Java is an object-oriented program, which means data and information in a program can be manipulated and used just like a real-world object. Objects in data can be assigned classes, states, and behaviors which can be used to quickly group, sort, and organize information.

A Closer Look at Arrays

An array is one way to group and sort information. An array is known as a container object which stores a sequential list of elements of the same type. Another way to look at an array is as a data structure designed to hold a specific amount of data or information. The array is a collection of variables which are all the same type. Values or items within an array are known as an element.

When an array is created in Java, it is assigned a length which is fixed. No additional elements can be added to the array after it is created. Each element in the array is assigned a numerical index which can be used to quickly access the element.

The Difference Between Arrays and Arraylist Java

Like an array, an arraylist is used to store and manipulate elements. Elements in an arraylist are assigned an index to help in retrieval and manipulating the elements.

Unlike an array, and arraylist does not have a fixed length. It will grow and expand as new elements are added. Arraylists are also known as dynamic arrays. This means you don’t need to assign a length when creating an arraylist. Even when specifying an initial length for the data structure, an arraylist can add indices to accommodate additional objects or data as they are added.

With an arraylist, as elements are added the list expands. When an element is removed the list shrinks. An arraylist can accommodate any amount of data, objects, or elements.

There are a few key characteristics to keep in mind as you work with an arraylist:

  • Arraylists and null and duplicate values: An arraylist can accommodate null and duplicate values. Keep in mind, null is neither an object or a type. It is a special value that can be assigned to a reference type.
  • Arraylists inherits class: An arraylist will inherit the AbstractList class. It will
    also implement the List interface.
  • Arraylists are an ordered collection: An arraylist is an ordered collection. As new elements are added the arraylist will maintain the order of elements. The arraylist allows random access to the list.
  • Arraylists and boxed types: An arraylist can be created using only boxed types, and not primitive types. Boxed types are data that can be wrapped in an object, so the data can be manipulated like an object. Primitive data types cannot be boxed, will not be treated like an object, and cannot have the characteristics of an object. Char and boolean are examples of primitive data types. Boxed data types can be automatically converted into an object and will be treated like an object with all the characteristics of an object. An Integer or Boolean are examples of boxed data types.
  • Arraylistsand synchronization: An arraylist is not synchronized. This means that when multiple threads are modifying the arraylist at the same time, the results will be nondeterministic. Deterministic results in Java are guaranteed and predictable. Nondeterministic results incorporate random, chaotic elements and cannot be predicted.

Arraylists are a powerful tool in Java programming. Because they create a dynamic array, they do require more memory and processing power than a standard array in Java. As long as you keep in mind the strengths and capabilities of the arraylist, they are a strong addition to your programming.


Constructors in Arraylist Java

Let’s dive into how you can implement arraylist java in your java programming.

We’ll start by looking at constructors for an arraylist java. A constructor in Java is a block of code that creates an instance of a class. In this case, an arraylist that can be filled with elements. Constructors for an arraylist include:

  • ArrayList(): This constructor builds an empty arraylist.
  • ArrayList(Collection c): With this constructor, the arraylist is initially populated with elements from collection c.
  • ArrayList(int capacity): This constructor will build an arraylist with a specified initial, or starting, capacity. Additional elements can be added after
    creation, and elements can also be removed to adjust the capacity.

Constructors are used to initially implement an arraylist, or dynamic array, in a program.


Methods in Arraylist Java

A method in Java is a block of statements that perform a function or task in Java. Methods are an easy way to reuse code. They simplify and save time in the coding process.

Let’s look at a few common methods for arraylist Java:

  • void clear(): This method removes all elements from the arraylist.
  • void add(int index, Object element): Use this method to insert a specific element in a specific index position in the arraylist.
  • Object clone(): With this method, you can return a shallow copy of the arraylist.
  • Object[] to Array(): Use this method to return an array that contains every element in the list in the correct order.
  • Boolean addAll(Collection C): This method will append every element from a collection to the end of the arraylist. The order that the values are returned is specified by the collection’s iterator.
  • Boolean add(Object 0): With this method, append a specified element to the end of the arraylist.


A Final Word on Arraylist Java

Java has become one of the most widely-used programming languages in the world. Java programmers are in-demand with many of the top businesses.

Arraylist Java and dynamic arrays are a fundamental tool in Java. Make sure to familiarize yourself with the capability and rules of arraylists.

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How to Use VBScript

Though you may not realize it, anytime you are using a Windows-based computer, you are working with VBScript.

Even though it is an older scripting language, it is still a popular tool, especially for system administrators.

It permeates the web and is found on pages across the internet. It’s a powerful scripting language for web pages that works on both the server-side or the client-side.

 

We’ll look at how VBScript works, and then discuss the ways you can use it today.

What Is VBScript?

VBScript, or Visual Basic Script, is a scripting language developed by Microsoft. It is based on Visual Basic working as a component-based scripting language. It operates like a simplified version of Visual Basic. With a fast interpreter that works on Microsoft platforms, VBScript utilizes a Component Object Model (COM) to connect with and use features in the system environment.

The COM accesses objects in the environment where it runs. For example, with VBScript you can access files using the FileSystemObject (FSO). This allows users to create, read, delete and update files in the Windows environment.

How Is VBScript Used?

Microsoft Windows system administrators will use VBScript to create tools for managing Windows-based computers. This includes functionality like error-handling, subroutines, and other basic administrator functions.

You can use VBScript to create scripts that run daily reports then deliver them to users across an intranet. Many office tasks that need to be run on a windows computer can be done in VBScript. With the right script, you can automate sorting, organizing, and data entry tasks.

VBScript is also the language used in Microsoft Excel. If you “hack” into an Excel file, you’ll be working in VBScript. Advanced Excel users will write queries and automation scripts for Excel in VBScript.

Since VBScript doesn’t need to be downloaded onto a Windows computer, it is often used to run scripts for automating software testing.

VBScript also works similarly to Javascript when it is used for client-side web development. VBScript is embedded in Internet Explorer (IE), so it can be used to create an executable script in HTML. It can be used to create applets and widgets for web pages.

Please note that not all web browsers are natively compatible with VBScript. Built-in support for VBScript is not included with Firefox and Opera. You’ll need to include cross-browser compatibility or some type of client-side scripting in these browsers. Many developers choose Javascript rather than VBScript.

The History of VBScript

VBScript was originally part of Microsoft Windows Script Technologies. Created for web developers in 1996, it was also used for system administrators who wanted a quick and easy automation tool that didn't require complex and time-consuming coding using programming languages like C++.

Over time, Microsoft continued to expand the functionality and use of VBScript, especially for system administrators. Regular expressions were added, including the With statement and functions like Eval, Execute, and ExecuteGlobal. Statements like these allowed users to execute scripts while another script was being executed.

VBScript and the Move to .NET

When Microsoft adopted the .NET framework, which includes a class library for Microsoft Windows that works with several different programming languages, Microsoft decided to include future support for VBScript as part of ASP.NET.

No new versions of VBScript would be developed. Only bug fixes and security updates would be offered. With Internet Explorer 11, Microsoft stopped support for VBScript, though an emulator was offered to provide support for VBScript in later IE releases.

For system administrators, the primary users of VBScript, Microsoft released Windows Powershell. Powershell is a tool that is like VBScript but with notable differences. It provides automation tools and system configuration functionality much like VBScript. It is not primarily a scripting language, but a shell with functionality that provides access to admin functions. Scripting functionality is more difficult using Powershell.

Many system administrators have been slow to adopt Powershell, citing the difficulty in learning how to script with it and problems with backward compatibility on older systems.

Despite the lack of support, VBScript is still included in all new releases of Microsoft Windows. Many users still turn to VBScript for automation tasks. These users don’t believe new releases will in any way diminish the usefulness and power of VBScript.

Features of VBScript

Let’s look at a few of the features and functionality you will find with VBScript.

1. VBScript Language

Since VBScript is based on Visual Basic, it provides the same language categories. These include:

  • Array Handling: Create and use data arrays.
  • Control Structures: Manage and regulate the flow of a VBScript script execution.
  • Constants: A name in VBScript that replaces a number or string and will not change in the execution of a script.
  • Date and Time Functions: Allows users to store and use Date and Time data for use in scripts.
  • Error Handling: Automates program execution to ensure scripts run error-free, efficiently, and smoothly.
  • Mathematical Functions: Basic math functionality like absolute values, sine, cosine, and tangent, products, and integral values.
  • Objects: Objects are class instances, with classes determining the variables, properties, procedures, and events of an object.
  • Procedures: A set of VBScript statements contained by declaration statements.
  • Regular Expressions: A function that identifies patterns in input text, with the pattern consisting of multiple character literals, operators, or constructs.
  • String Manipulation: VBScript includes several built-in methods for processing strings.
  • User Interaction: VBScript offers methods of interacting with users. This could include input box for collecting data or entering values, or a message box for displaying information.
  • Variables: A memory location that contains a value that can be changed or modified during script execution.

The VBScript has a few other identifying features. The main construct in VBScript is the procedure. This separates code into smaller modules that perform an action.

A function in VBScript delivers a result to a statement. A subroutine does not deliver a result. Parameters in VBScript are positional and can be delivered by value or reference.

Coding in VBScript includes constants. These constants include vbYellow and vbBlack for color values, True and False for logic values, vbOKCancel and vbYesNo for MsgBox codes. VBScript includes many other constants, which aid in the readability and ease of use of the script.

2. Functionality in VBScript

VBScript provides easy access to a number of features and functionality. These include:

  • Network Printers
  • Network Shares
  • Network User Information including groups and membership ID
  • Commonly accessed folders like Desktop and Documents
  • Named and unnamed command line arguments
  • Functionality for runtime execution of text, such as Eval and Execute
  • A method of embedding a VBScript language in another application, allowing error reporting and a debug mode
  • Windows Management Instrumentation (WMI)

Many of the features and functions found in VBScript focus on the Windows system administration capability.

VBScripts ease of use and native capability make it a powerful tool for managing networks, especially for Microsoft users. It allows for easy automation of basic office tasks, such as monitoring computers using Windows. Server administrators also like the automation and monitoring capabilities found in the basic VBScript functionality.

3. Other Functionality in VBScript

VBScript uses Scripting Runtime Library (scrrun.dll) for file system management, modifying files, and streaming text operations. Using the Scripting Runtime Library, you have access to objects like File, FileSystemObject, and Textstream allowing access to the Windows file system.

VBScript also allows functionality using ActiveX. Database access is provided through ActiveX Data Objects (ADO). Security concerns have hurt adoption of ActiveX, but it is still available in limited cases through VBScript.

The “ADODB.Stream” class provides binary file and memory I/O functionality. This provides string builders and interconvert byte arrays and strings.

VBScript is currently the base scripting language for Quick Test Professional, a widely-used software test automation tool. It provides a quick and easy way to write automated test scripts for several applications.

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Source: Freepik.com

Where to Execute VBScript

VBScript can only be executed in a compatible host environment. This is typically not a problem, as Microsoft Windows offers several native environments. These include:

  • Internet Explorer (IE): With the release of IE 11, Microsoft no longer included support for VBScript. An emulator which can be added to IE does provide a compatible host environment.
  • Windows Script Host (WSH): A tool in Microsoft Windows that provides scripting capability and a range of additional features.
  • Internet Information Services (IIS): A web server designed by Microsoft to support Windows NT products.

In addition to these environments, it is possible to embed a VBScript hosting environment in another application, using tools like Microsoft Script Control (msscript.ocx). This is a powerful feature for building web applications.

A Final Word on VBScript

When VBScript moved to ASP.NET support, many felt the scripting language would soon be forgotten. It has continued to be a popular tool, especially for system administrators and software testing professionals.

Even with the move to implement other tools like Powershell in place of VBScript, users continue to rely on this older scripting language. VBScript is much easier to use. It is widely accepted by users and provides more than enough functionality without the complexity and problems of other tools.

For now, there is little reason for users to adopt or implement a different solution when VBScript works so well. Even with no new expected updates coming for VBScript, it will continue to be the go-to solution for many administrators.

Top 15 Most Common MVC Interview Questions

Are you looking for a job in coding and programming?

According to recent studies, the most desirable programming jobs are in high demand, with new graduates and experienced coders flocking to some positions.

 

There are steps you can take to position yourself for success in the job hunt. There are skills that employers are looking for in a new hire. With a little study and preparation, you can get an edge over the competition for a new job.

One skill that companies are looking for, but many candidates don’t consider, is the architectural pattern Model View Controller (MVC).

 

We’ll study MVC and then look at the interview questions and concepts you might be expected to understand during an interview. In each section, we’ll provide you with some of the top MVC interview questions so you can be prepared. Consider this the edge you need for the job you want.

What Is MVC?

MVC isn’t a programming language. Instead, it is a way of modeling development work.

Model View Controller divides an application into three connected parts. It looks at how information moves through an application, and how a user will interact with it.

Using this model, MVC breaks down software and programming into tasks. This is another way of looking at the work necessary for a successful programming. MVC promotes code reuse and enables development teams to work in parallel. It provides a better way of managing work.

A History of MVC

MVC began more than 40 years ago when Trygve Reenskaug included the concept of Model View Controller in the programming language Smalltalk-76 while he was at the Xerox Palo Alto Research Center.

Reenskaug’s goal was to bridge the gap between a mental and a digital model of complex systems, especially for graphical user interfaces. He wanted to help users manage the computer system in a more visual and intuitive way. MVC promoted that goal during the development process.

Other developers continued to refine the MVC model with later versions of Smalltalk. MVC wasn’t presented as a general concept to the public until a 1988 article in The Journal of Object Technology.

Since that article, MVC has found a place in coding and development. New variants like the Hierarchical Model View Controller (HMVC) and the Model View Presenter (MVP) have been developed. MVC has become an important tool for Java Developers, especially when NeXT’s WebObjects, which used MVC, was ported to Java.

Today, MVC is utilized in the architecture of web applications across the internet. Many of the programming languages in use today, like Java, Ruby, Python, Spring, and Rails incorporate the concepts of MVC.

Top MVC Interview Questions

  • What does MVC stand for? Model – View – Controller.
  • What programming language originally incorporated the concepts of MVC? Smalltalk.
  • What other languages in use today incorporate the concepts of MVC? A sampling of languages includes Java, Ruby, Python, Rails, and Spring.
  • What are some variant models of the MVC architecture pattern? HMVC or Hierarchical Model View Controller. MVP or Model View Presenter. MVA or Model View Adapter.
  • Where is MVC used in programming, development, and coding? It is the basis of many web applications. You can also find the concepts of MVC in desktop programs and mobile applications.

How MVC Works

The basic concepts presented here are a rich area for many MVC interview questions.

Like other architecture patterns used in software development, MVC outlines a solution to a problem. It offers an answer that can be adapted for every system. This means there are differences between specific MVC architectures. There isn’t a single, accepted definition of MVC. There are core fundamentals which we describe here.

MVC divides software concepts into their separate development tasks – Model, View, and Controller. These concepts define the fundamental structure of a web application, as well as many mobile apps and software programs. It models how a user will interact with the system, providing methods of control over the application.

The tasks include:

  • Model: This is the dynamic data structure of the application. It manages the information and logic within the application. This is the data the user intends to manipulate and control.
  • View:  This is the output of the data. Consider it a visual depiction of the model. It may be a chart or a graph presented by the application. The View highlights some qualities while suppressing others using a presentation filter.
  • Controller: This is the link between the user and the system. The Controller accepts input from the user and passes it to the model.

There is a pattern to how the three components of MVC will interact. MVC defines these interactions:

  • The Controller receives input. If necessary, the Controller will validate the input and then pass it to the Model.
  • The Model will manage the data in the system. It takes the input from the Controller as direction for the data management. Once the data is ready, it will send the result to the view.
  • The View will receive the result and then present the data in the necessary format.

This cyclical model has become the basis of most web applications.

Top MVC Interview Questions

  • How does the Model work in the MVC architecture pattern? Model is the data structure in MVC and an application.
  • How does the Controller work in the MVC architecture pattern? The Controller receives the input from a user in MVC and an application.
  • How does the View work in the MVC architecture pattern? View formats the data and then presents it in a graph, chart, or other presentation.
  • How does the Model, Controller, and View interact in the MVC architecture pattern? It is a cyclical model. The Controller receives input and sends it to the model. The Model receives input and manages the data before sending it to the View. The View formats the data and presents it to the end user. The end user receives the View and sends input back to the Controller.
  • What does MVC model in a software system? The MVC will model user interaction with an application.

Advantages and Disadvantages of MVC

As popular as MVC has become, it is not the only architecture pattern used in development. Just like any other skill covered in an interview, employers want to know that you are well-versed in the advantages and limitations of MVC.

The advantages of MVC for software development and programming include:

  • Using the MVC model, multiple developers can work at the same time on an application. Work can be divided across the components, allowing for parallel work. This means faster development.
  • Thanks to the division of labor, new developments or modifications are easier to make. Making a change to the development plan won’t impact the entire project. Instead, change can be better managed with the results organized across the MVC components.
  • With MVC, you can develop multiple views of a model. This gives you new approaches for accessing and developing an application.
  • With multiple models, you can reduce code duplication since business logic and data is separated from the display.
  • MVC promotes and supports asynchronous programming. This means code can be written to eliminate “blocking” in an application. The application can manage multiple actions at the same time, without waiting for a previous action to finish. Applications work much faster with asynchronous programming.
  • The MVC model allows data to be returned without formatting. A model can be used in different applications and with different interfaces. It can be reused with minimal changes or adaptation.

As powerful as MVC has become for developers, there are disadvantages to using it. These include:

  • Developers need to be proficient in multiple technologies in order to manage and coordinate the teams working simultaneously on a project. This could include the client-side code and HTML.
  • Using MVC to model a project will increase the complexity of the work. This doesn’t mean the project will be more difficult, but it does require a deeper understanding of user interaction than some development teams are willing to accept. Often, a team will need to use additional architectural patterns and models than MVC, leading to additional complexity.
  • You need to ensure consistency across multiple representations of the development model. Changes made to the View may impact the Model, for example. Changes to the Model may require adaptations to the Controller and the View. This will require coordination between the teams to manage.
  • Isolated development teams can sometimes lead to delays in the development process. The work of one team may be delayed by the actions and decisions of another team. Again, this can be mitigated with coordinated work and management of the project.

When using MVC for a development project, it is important to consider the advantages and disadvantages of the model. Focus on the strengths of MVC, and then address the disadvantages.

Top MVC Interview Questions

  • What is a primary advantage of MVC, and how can you maximize this advantage on a project? MVC allows multiple project teams to work simultaneously on a project. This enables rapid software development. Having the resources to support multiple teams, with skill in multiple technologies, is critical for a successful MVC project.
  • What is the connection between MVC and asynchronous programming? MVC supports asynchronous programming. This allows multiple actions to occur simultaneously in an application without the blocking that can delay results.
  • How does MVC reduce code duplication in development? MVC separates business logic and data into separate project components. This reduces code duplication.

Using MVC in Development

An important part of any interview is identifying how you will use a skill for practical applications. Are you able to incorporate MVC concepts in programming and development?

In this section, we’ll look at how MVC works in day-to-day development tasks.

1. Problem Solving

Many companies find MVC critical for breaking down the user interface of an application. It looks at each component of an application separately, allowing a team to look at the individual parts. Many developers report that problems are easier to solve when you look at the pieces rather than the whole.

2. Improving Productivity

MVC is a clear advantage to rapid software development and increased productivity. Allowing work to be completed on an application using multiple teams can accelerate progress. It also allows work to be completed in parallel. Managing the teams and coordinating the work is important to consider before implementing MVC.

3. Decision-Making Process

MVC promotes multiple views of an application and the user interface. As each component of the user interface model is considered, you can evaluate the advantages and disadvantage of each before selecting the model that delivers the most benefit for the application and users.

4. Strengthens Teamwork

While MVC is a software architecture pattern, it is also a way of building and creating a team focused on a single goal – delivering the best application possible. Consider how to manage the work between teams. The individual work of teams and mismanagement of changes in a project can lead to delays. Consider how you can use MVC to promote teamwork and reduce the complexities and delay associated with MVC.

Top MVC Interview Questions

  • How can you use MVC to manage the work and teams during the development process? MVC separates the application into component parts that can be used to delegate work to teams. Coordinating the work between teams is the responsibility of project leadership.
  • How can MVC promote problem-solving during development? By looking at the individual components that make up a user interface, it is easier to identify the solutions to a problem. You will also have multiple views of a model when seeking a solution.

A Final Word on MVC Interview Questions

MVC has been a powerful tool for developing and building web applications. Many programs rely on the graphical user interfaces (GUI) that are shaped and improved using the MVC architecture pattern.

If you are looking for a job with many of the top software and technology companies in the world, MVC will likely be a critical skill the business will look for in candidates. Take the time to understand how MVC works, and what the top MVC interview questions might be before you interview.

What Is Java Static?

Today, there is probably no more widely-used programming language than Java.

It has become the standard language for businesses and the enterprise. It provides a solid foundation for much of the internet and many programs used across the world. It has fueled the rise of mobile applications.

According to the job site Indeed.com, there are more postings for Java programmers than any other language.

We’ll look at Java, and then dive into Java Static, one of the core features of Java.

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How Is Java Used?

Many experts agree that the key to Java’s popularity is code reusability and ease-of-use.

Before Java, programmers would need to write new code for every platform that ran a program. You would need a Linux version, a Windows version, and an Apple version of a single application. This led to a much higher cost in time and money for a program, or severely limited availability.

Java was designed to lower the costs of programming. It offers several advantages over other languages. These include:

  • Platform Independence: Rather than running completely on the platform, a Java program uses a Java Runtime Environment (JRE) that can be easily downloaded. This means any platform that can download JRE can run a Java program. Linux, Windows, Apple, smartphones, mainframe computers, and more can all use Java. Programmers using Java can write a program once and have it run on any platform that uses JRE.
  • The Java Class Library: Java is not a difficult language to learn or use, but it provides a library of classes that deliver a wealth of standard utility functions. Classes can be used in programming to create objects. This library is known as the Java API. While Java uses only 50 keywords, it has thousands of classes. Using the API, you have a massive number of methods for programming. In fact, other languages use the Java API tools, including Jython, JRuby, Scala, Groovy, Redline, and Smalltalk.
  • Java and Objects: Java is a fundamentally object-oriented programming language. The language uses elements known as objects for programming. Each object represents a concept or a real-world construct. Each object contains data known as a state and a behavior that can be used in tasks known as methods. For example, you could have an object known as a book. It could include data on the author and publication date. It could include methods like read or add a new chapter.

These core features in Java provide a clear advantage to programmers. It offers clear benefits over other languages with enough features and functionality to manage almost every programming need.  

What Is a Java Static Keyword?

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Java static is a type of keyword in Java. It provides a non-access modifier for members that include blocks, variables, methods, and nested classes. Once a member is made static, it can be accessed before objects in its class are created without any reference to any other object.

The static member is in a class by itself and isn’t associated with any other members of the class. This means you can use and access the static member before you create the class instance.

There are multiple types of Java static members. There are differences in how they operate in Java.

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1. Java Static Fields

A field in Java can be declared static using the static keyword. The position of the static keyword is interchangeable with the visibility keywords – private, protected, and public. Typically, the visibility keyword is used before the static keyword.

Another way to look at static fields is that a single instance of the field is created and is then shared by all the instances of the class. No matter how many times the class is initialized, that single, static field will be shared across them.  

This means that In Java, the value of a static field is the same across all instances of a class. For example, if you have a class in Java with a static field called Name, then all objects in that class will have the same value in the field Name.

Typically, Java static fields are used when the value of a variable is shared across all objects. It is also used when the value is independent of the object or objects. Also, static field variables may only be declared at the class level, and do not require object initializations. They are accessed directly using the class name.

In most cases, the static field is created when the class is first loaded in Java. This occurs when the first static member in the class is referred to, or when the class is first created. The Metaspace stores the static variables In JVM (Java Virtual Machine).

2. Java Static Method

A method can also be declared using the static keyword. Static methods are linked to the class, and not a specific object in the class. This allows you to create an object from the class without having identified the static method defined by the class.

Typically, Java static methods are used by operations that can be performed independently of instance creations. This means code that is written and shared across all instances of a class. Java static methods are often used in creating helper and utility classes.

An important rule for static methods is that you can access a nonstatic field or nonstatic method using a static method. The static method will not have an instance of the class to reference the methods or fields. Also, note that static methods are implemented when they are compiled. Since you will override the method as part of Runtime Polymorphism, you cannot override static methods.

One common use for a Java static method is Main. Main is used by Java runtime to start an application. This method is static, so applications running Main use the static method automatically.

3. Java Static Block

A Java static block is used to initialize static variables. When a static variable uses additional, multi-statement logic, it is best to use a static block. For example, when you want to use pre-defined values before initializing a list object, then a static block will allow you to initialize the variables with the declaration.

Static blocks are a powerful tool for initializing static variables that may be error-prone and require additional exception handling, or when the static variables require additional logic.

In Java, a class can use multiple static blocks for initializing static variables.

4. Java Static Class

Java is a little different than many programming languages.

One feature of Java is the ability to create classes within classes. This is an excellent way to group elements that may be used only occasionally. It reduces the complexity of the code, making it both readable and orderly.

Creating a class within a class can be accomplished using nested classes that are static. These are called static nested classes. When a nested class is declared static, it can only access static members in the outer class. In this way, they behave like other top-level classes except that they can only be accessed by the enclosing class.

Nested classes that aren’t static are called inner classes. Inner classes can access and use all members of the enclosing class.

Typically, static nested classes are used near the class that will use it. Grouping them together increases readability and reduces the strain on system memory. Also, please note that a top-level class cannot be declared as static. Only nested classes can be declared static. They cannot access any instance members except through an object reference.

A Final Word on Java Static

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Java was first released in 1996. It is more than 20 years old, and yet it continues to be a popular and powerful programming language. It not only endures but thrives as a powerful tool for programmers across the world and in almost every industry and vertical.

Other languages have fought for the top position, languages like C++. There are places where another programming language will deliver greater value. C++ continues to have a place in gaming, mainly because of the high hardware performance it offers, and the control of resources C++ can deliver.

There are languages growing in popularity, like Ruby and Python which are popular in building websites. Ruby and Python handle and automate many of the repetitive tasks in programming, making them extremely easy to use.

No other language has had the continued popularity and widespread use of Java. An important reason for the popularity of Java is the practical nature of the language, and the reliability and performance of the programming. Java static keywords are an example of this practicality and performance.

Java static keywords eliminate the need for repetitive coding for repeated variables. Static keywords reduce the burden and weight on system memory. It’s another example of how Java can deliver programming results quickly and easily. Java reduces the strain on resources, both memory and system processing, and the programmer.

If you are a Java programming, consider how Java static keywords can benefit your work.

How to Use ForEach in JavaScript

JavaScript is one of the most popular development tools or languages in use for creating websites and client-side applications today. Its capabilities and power are demonstrated through JavaScript’s presence in social media sites such as Facebook and Twitter, as well as adoption by powerful search engines that include Google.

 

As a JavaScript developer, you’re always on the lookout for tips, tools, and methodologies that can make your software engineering life easier, more productive, and more efficient.

 

Among these techniques is the appropriate use of JavaScript’s “foreach” method of handling arrays and controlling program flow. You probably are quite accustomed to using the “for” loop in your programming, but there are several nuances and scenarios where the foreach method may contribute to a more efficient way of coding for your application.

What is the ForEach Method?

Foreach is a coding method that controls the flow of logic when handling an array or some collection of sequential elements.

As with the for logic method, foreach in JavaScript is utilized to perform a certain set of logic or an operation on the input elements. Unlike a for loop, foreach utilizes no counter or iteration value to control the execution of the loop. Foreach essentially tells the program to perform the specified logic on every entry in the collection of elements.

By comparison, JavaScript’s for loop includes a combination of three parameters or statements, defining the execution of the logic to be executed through the loop code. For example:

  • For (i = 0; i < 20; i++) {  }
  • i = 0 initializes the iteration to 0
  • the loop will execute as long as the iteration index remains less than 20
  • i++ will increment the iterator by 1

Logic coded between the brackets will be executed for each iteration of the loop. This basic functionality of loop processing is a powerful and useful cornerstone of JavaScript. It has been utilized for its versatility in creating iterative code by practically any developer who was to put fingers to a keyboard.

The trick when coding a for loop is knowing where to set the iteration value – setting it too low could result in fewer than all elements in the input array being successfully processed through the intended logic of the function.

ForEach operates in a different manner, giving you a method that can perform a function on every element in an array, map, or set.

The most common use of foreach method is to loop through a sequence of elements and perform the same logic for every element in the array or collection. There is no explicit counter for the number of items to be processed through the foreach loop – every element is processed.

Here is a simple illustration of JavaScript code utilizing a for loop vs. a foreach method:

var sample_array = ['a', 'b', 'c'];

        for (var i=0; i<sample_array.length; i++) {

            console.log(sample_array[i]);

            //a b c

        }

        sample_array.forEach(function(current_value) {

            console.log(current_value);

            //a b c

        });

ForEach Syntax in JavaScript

Foreach processing is supported in many languages besides JavaScript, although the details of the syntax vary from one language to another.

In JavaScript, the syntax for the foreach array method takes on the following syntax:

Array.forEach(function (currentValue, index, arr), thisValue)

Parameters include:

  • Function – the function that will be executed for each array element – this is referred to in JavaScript as the callback function
  • currentValue – this is the value of the current element
  • index – (optional) array index of the current element
  • arr – (optional) the array object the current element is part of
  • thisValue – (optional) a value that you want to pass to the called function as its “this” value

AppendTo.com provides you with some very basic examples of coding foreach loops, which will give you a good foundation for the syntax and construction of this method.

How to Use ForEach in JavaScript

Now that you know what foreach does, how do you use it effectively?

You need to be aware of certain factors that apply to using foreach methods on arrays:

  • forEach() sets the range of elements to be processed in the array before execution starts with the first element. This means that any elements that get added to the array after execution begins will not be processed by the foreach loop.
  • If the content or values of array elements change after execution begins, the value recognized by the called function will be the value at the time that element is executed.
  • If elements in an array have no values, the function is not executed.
  • Also, elements that are deleted from the array before they are processed through the function will not be processed.
  • Another caution – if elements that have already been processed are deleted, the process of shifting elements in an array will cause elements later in the array to be omitted from processing. To illustrate this effect, imagine an array that contains values of 10, 20, 30, and 40, and logic that is to summarize the values. If the second entry is deleted, while processing the array in a foreach loop, 30 and 40 will be shifted up. With the element containing 30 now in the second position, it will be skipped.

Foreach does not make a copy of the array before executing the loop, which could subsequently impact your results. This may not be an important factor in your application, but you must be aware of the condition.

Foreach method will not alter the content of the original array, although the function called may do so.

Each of these attributes of foreach processing is important to your programming design, especially when working with arrays that may be highly volatile in nature.

ForEach Browser Support

Nearly every popular browser supports the forEach JavaScript method, depending on the version in use:

  • Google
  • Internet Explorer (Ver. 9.0 and higher)
  • Firefox (Ver. 1.5 and higher)
  • Safari
  • Opera

Browser compatibility makes use of the method nearly universally acceptable for your web page or other application development use.

Reasons to Use ForEach in JavaScript 

There are reasons you may want to elect to use foreach methods in your code over other options including for loops:

  • Readability – many developers view foreach loops as more comprehensive when reading code
  • Lines of code may actually be reduced, with no need to define extra variables for controlling iteration
  • Speaking of iteration, foreach reduces the likelihood of making mistakes with index handling, such as setting an index to 1 instead of 0, also known as “off-by-one” errors. The result can be a loop that includes one too few iterations, or one too many.

On the other side of the coin, there are instances where you may want to break out of a loop early, before processing all entries in an array. This could be where you’re searching for a certain name, and want to break out once you encounter it, rather than stepping through every element in the array. For loop has an easy method of breaking out of the iteration.

Breaking out of a ForEach Method in JavaScript

Can you break out of a foreach loop? Yes, there are methods available to break out of a foreach loop, such as forcing an exception based on detecting some condition.

Like many developers, you may view this as contrary to why you would utilize the foreach method over a standard for loop, since throwing an exception is not a “clean” programming methodology or best practice. This is stated very plainly in an MDN Documents page:

“There is no way to stop or break a forEach() loop other than by throwing an exception. If you need such behavior, the forEach() method is the wrong tool, use a plain loop instead. If you are testing the array elements for a predicate and need a boolean return value, you can use every() or some() instead.”

A full discussion on breaking out of foreach methods and alternatives is available online, as well.

Learning More About ForEach in JavaScript

There are other variations of foreach methods available to you, if processing an object other than an array:

NodeList.forEach() performs the same function as the array foreach method, but utilizes a NodeList as opposed to an array.

There are many examples and tutorials online for developing your skills in the use of foreach in JavaScript, and YouTube offers many videos with examples and discussions on the use of the method.

What Does the JavaScript Split Do?

JavaScript is perhaps the most popular scripting language in use for client-side web page development, world-wide. It continues to evolve and add features that enable new functionality and performance improvements, providing developers with enhanced toolsets for building robust, efficient applications.

 

One of the areas where JavaScript shines is in the management and manipulation of arrays.

One method available to you is the split() method. This method has been included in the JavaScript library of methods ever since the ECMAScript 1 standard. ECMA (European Computer Manufacturers Association) sets the standards for scripting languages, with a special focus on JavaScript standards.

 

JavaScript is the most well-known, popular technology that forms the basis for the ECMAScript Language Specification. The ECMA Standard is continuously evolving, now in its 9th edition, formalized in June of 2018, with contributions from many members of the development community.

JavaScript Split Method – What it Does 

JavaScript provides the split() method to split a string into an array comprised of substrings, returning the new array to you.

Split syntax is very simple on the surface:

string1.split(separator, limit)

  • string1 – the name of the original string to apply the method to
  • separator – the character to be used for executing the split of the string. If this parameter is not provided, the result will be an array with one item, which contains the entire original string. The separator is not limited to a single character. If you specify a separator with more than one character, the exact and entire string of the separator must be found before the split point will be recognized.
  • limit – this optional value specifies the maximum number of splits to be generated. The split method stops when the limit is reached. If the split execution reaches this limit, no additional items will be included in the resulting array, so all data from the original string will not be represented.

Results – after the split is performed, the result will be an array containing the values that have been split.

Programming notes:

  • Split() method does not alter the original string in any way
  • Split() can only be used with strings, not arrays
  • If you provide an empty string for the separator value (“”), the result is that the string is split between each character.

A simple example:

var string = "Hello reader how are you?";

var result = string.split(" ");

Your array result:

Hello,reader,how,are,you?
 
Let’s try another example, omitting the second parameter this time:

var string = "Hello reader how are you?";

var result = string.split();

 
Now the result will appear in your array as:
 
Hello reader how are you? – as you can see, the entire string has been “split” to the new array
 
This time let’s try the same string, with a blank separator, and take a look at the result:
 

var string = "Hello reader how are you?";

var result = string.split("");

 
Your resulting array:
H,e,l,l,o, ,r,e,a,d,e,r, ,h,o,w, ,a,r,e, ,y,o,u,?
 
Each character in the string has been split, including the spaces between words.
Notice that since a space was not used as a separator, the spaces are retained in the resulting array.
 
Adding in the parameter to limit the split to 3 values:
 

var string = "Hello reader how are you?";

var res = string.split(" ", 3);

Results:

Hello,reader,how

Now let’s use a split value such as the letter “e”:

var string = "Hello reader how are you?";

var result = string.split("e");

Here is the resulting array:

H,llo r,ad,r how ar, you?

Putting the JavaScript Split Method to Use 

Now that you know the basics of what the JavaScript split does, you need to know how to use it in your application.  The split method is sometimes confused with JavaScript’s slice and splice methods, so it’s important to understand specifically what the JavaScript split does.

JavaScript slice() and splice() perform their functions on arrays, where split() works with strings, dividing a string into substrings, then returning the results in the form of an array.

programming code

Source: Freepik.com

Split method coding is very simple, with only minimal parameters needed to perform its function. Putting the method into practical use can be a little more complicated, once you apply a separator and begin to evaluate the results returned in the array.

One of the most common uses for using split is using the method with empty parameters:

Mystring.split()

This returns a comma-separated array for each character from the original string, which you can subsequently access by index for easily working with the array.

Determining the number of elements in the array is an effective tool for evaluating how many fields were returned in a keyed entry in your web application. A good example would be finding the first and last names entered in a web page string.

You may also find this method very useful in splitting the contents of a hyphen-entered phone number:

var inp_phone = “ 614-555-1212”;

var phone_split  = inp_phone.split(“-“);

Your new array will contain the numeric portion of the phone number, with the hyphens split out

Another common use would be to split an email address, to drop the “@” element from your resulting array:

var inp_email = “President@whitehouse.gov”;

var email_split = inp_email.split(“@“);

the resulting array will omit the “@” value, containing: President, whitehouse.gov

Browser Support for JavaScript Split

You can utilize the split method in JavaScript freely, as all popular browsers support the function:

  • Chrome
  • Internet Explorer
  • Firefox
  • Safari
  • Opera

When to Use the JavaScript Split Method

String objects are usable by many functions in JavaScript, but others are only useful in handling and manipulating information in arrays. String methods include:

  • match
  • search
  • repeat
  • substr

There are, of course, many other methods that function with string content. While some do not have an impact on the original string, others can transform string data, such as toLowerCase() and toUpperCase().

But there are many instances when you need to work with information in an array. Split() method is the tool that can transform string data to an array, even providing powerful selection as it performs the string-to-array transformation.

Arrays are a basic element of JavaScript, and contain variables of multiple types. Presenting information in arrays offers all the flexibility you need for building complex web applications

Knowing your data content is key to the most efficient context of your split method. Special characters contained in your string could potentially alter the results of your array if they duplicate the character you specify as the separator.

Unique Ways to Use the JavaScript Split

If the separator you provide is a regular expression that includes capturing parentheses, each time the separator matches, the results of the capturing parentheses will be spliced into your output array.

An array may be used as a separator in the split to extract string content that contains the array elements.

Split can also be utilized to reverse a string, although this may not be the most effective way to accomplish such reversal.

It’s important to select your separator carefully, due to the nature of how split process the string and the results that appear in your array when the value or separator array are encountered in the data.

Are There Times When You Should Not Use Split?

Certainly, if your data is in a string, and standard JavaScript string methods will suffice for your application, the split function is unnecessary. Performing the function will utilize cycles and add memory requirements for the new array, both of which can be avoided.

When your data is unknown or contains unpredictable characters, use caution with the split method, since separator values could encounter data that produces results that negatively impact your application.

Becoming Proficient with JavaScript and Split

Examples and discussions of how some developers have addressed challenging or unexpected exception conditions are available on JavaScript community websites and online video tutorials.

If you need more details, you can always invest in a JavaScript course at a local community college, pick up a good JavaScript book, or even take online courses.

Each of these educational options can open doors to a rewarding and lucrative career as a JavaScript developer, one of the most in-demand technical positions in the industry today. Indeed.com alone lists openings for over 40,000 JavaScript developers nation-wide, in full-time, part-time, and contract positions.

Developing your JavaScript skills with a working knowledge of split() and other methods may get you on your way to a promising development career.

Java Tips: How to Convert String to Int

Java gives you all the tools you need to create robust, high-performing websites and applications for a variety of devices, from enterprise mainframes, to tablets, to smartphones and other mobile devices.

 

Building such applications, of course, includes accepting data from users in the form of keyed or uploaded data to be validated and processed by your programs. Data comes in many forms that include characters, numbers, and symbols.

Java supports multiple forms of data, among them are string and integer objects. One of the data objects most commonly utilized for accepting and working with data is the basic form – a string object.

 

But to utilize string data for specific purposes such as performing calculations or storing in database fields that have numeric properties, the string content must be transformed to an integer object. Attempting to perform an arithmetic function on a string object will get you in trouble with an error occurring immediately. You must first transform the numeric value in the string to an acceptable data type.

 

That being the requirement, the question is – how to convert string to int object content.

 

Java Has Options to Convert String to Int

Regardless of how new you are to Java programming, it’s quite likely that your first experience will require the function of performing numeric operations on data that is initiated in a string object form. Knowing how to make the conversion to fields you can treat as numbers will be critical to writing a successful application.

Java provides multiple ways to transform string content into integer objects. There are multiple types of integer objects, to make the subject more confusing. Java provides four primitive integer types that store whole numbers of varying sizes:

  • Byte – 1-byte integer that can contain a range of values from -128 to 127
  • Short – 2-byte integer with a range between -32,768 to 32,767
  • Int – 4-byte integer with range between -2 billion and 2 billion
  • Long – 8-byte integer with range between -4,000 trillion to 4,000 trillion

The most common selection for an integer object is int, due to its range for most numeric values

When you know a small value will be used for a particular function, byte or short can provide an efficient use of memory. Long is an exception, but may be applicable for some applications.

These data types indicate to your program not only that the field is a numerical variable, but also the range of values it can contain, and the operations the variable can be have performed on it.

The issue is that it’s often the case that you begin with a string data type, which must be transformed to an integer type to perform numeric functions. Two options are available to you in Java:

Option 1 – Integer.parseInt()

A simple example:

string number = “50”;

int result = Integer.parseInt(number);

the result will be a primitive integer with a value of 50

The parseInt syntax is:

parseInt(string s, int radix)

s = the string to be converted to an integer – the sign needed for the integer may also be specified

radix – the radix to be used during string parsing

You can also perform a simple conversion from string to an integer with this function:

parseLong() – parses the string to Long integer data type

Option 2 – Integer.valueOf()

String number = “50”;

Integer result = Integer.valueOf(number);

The result is a new integer object with a value of 50

Integer.valueOf syntax is:

Integer valueOf(int a)

This results in a new integer representing the parameter a

The same syntax applies to variations of the valueOf and parse functions for other data types:

  • Short.valueOf
  • Long.valueOf
  • parseShort
  • parseLong

The primary difference between parseInt and valueOf functions is that parseInt returns a primitive int, but valueOf returns a new integer object. In fact, valueOf actually uses the parseInt function behind the scenes.

With either of the options, if the string contains a value that cannot be parsed to a valid integer, the code will throw a NumberFormatException error.

  • String1 = “Hello world 12345”; would result in an exception
  • String1 = “12345”; will be parsed without and exception being thrown

Due to the potential for any string containing a value that cannot legitimately be parsed, your code should always either:

  • Validate the string content prior to attempting to convert a string to int.
  • Handle the NumberFormatException within your program.
  • Strip any invalid characters from the string before parsing (possible logging a warning that data has been omitted).

Selecting the Right Type of Java Int Object

With the multiple options available to you for numeric variables, you need to be cautious in the object type selected for individual functions.

Values that you know will be small such as counting entries on a web page screen may easily be contained within a byte or short data type. Int type will handle most typical application values, but if you may encounter large values, long data type can be your best option.

If you opt for a smaller capacity data type but encounter larger values, you could conceivably overflow the capacity of your integer object.

Examples of How to Convert String to Int?

You have the basics now for functions that allow you to convert strings to numeric variables using integers of different types, so let’s look at some additional examples to illustrate the coding.

Additional example1 using Integer.parseInt()

String strTest1 = "500";

    int iTest = Integer.parseInt(strTest1);

    System.out.println("Original String:"+ strTest1);

    System.out.println("Converted to Int:" + iTest);

This routine will result in the original string of “500” converting to the integer object iTest, displaying both the original string and new integer

Additional example2 using Integer.parseInt()

String ostr="123";

                int inum = 456;

                /* convert the string to int value

                 * ,making the value of inum2 123 after

                 * conversion

                 */

                int inum2 = Integer.parseInt(ostr);

                int sum = inum+inum2;

                System.out.println("Result is: "+sum);

Additional example1 using Integer.valueOf()

String strTest1 = "1000";

    int iTest = Integer.valueOf(strTest1);

    System.out.println("Original String:"+ strTest1);

    System.out.println("Converted to Int:" + iTest)

Additional example2 using Integer.valueOf()

String istr="-234";

                //int variable

                int inum1 = 110;

                /* Converting String to int in

                 * the value of variable inum2 negative after

                 * conversion

                 */

                int inum2 = Integer.valueOf(istr);

                //Adding up inum1 and inum2

                int sumo = inum1+inum2;

                //displaying results of sumo

                System.out.println("Result is: "+sumo);

Final results of the valueOf and parseInt methods of converting string data to int objects are the same, aside from the type of the object returned.

In Summary

In order to perform any numeric functions such as arithmetic on an object in Java, the information must be in contained in a valid numeric object type. Even if a string contains all numeric data, an error will occur if you try and use it for any type of calculation.

programmer working on codes

Source: Freepik.com

You can perform this conversion from string to int with two Java coding methods:

  • Integer.valueOf(string)
  • Integer.parseInt(string)

The difference between the two:

  • parseInt returns a primitive int value
  • valueOf returns an Integer class object with the converted value
  • valueOf may optionally contain a negative value, provided by a minus sign

Regardless of the method you choose in your Java development efforts, the primary considerations to keep in mind are:

  • Be sure the int object you define from the string conversion has the capacity you can conceivably extract from the string – if in doubt, use a larger data type.
  • Select an integer type that will allow all functions and values you anticipate, such as negative values or floating point operations.
  • Verify the string contains valid data that can be parsed successfully, or at least include code to detect any exceptions thrown from a conversion error.

More Details for Java Conversion String to Int

There are many great resources available to you as a Java developer, to gain additional knowledge of how to convert string to int values.

Each of these options will provide an amazing array of how-to instructions on Java programming topics, with a variety of examples, drawing from the experience of seasoned Java developers.