JAVA File Extensions: All You Need To Know!

If you’re a developer, chances are you’ll be familiar with the Java programming language. It’s popular for its portability, scalability and vast library of open-source code. But when it comes to understanding file extensions associated with Java development, the situation gets a bit tricky. In this blog post, we will discuss JAVA file extensions in detail and explain how they can be used to your advantage as a developer.

We will also talk about the different types of file extensions available in JAVA and their significance in software development. So read on to find out all you need to know about JAVA file extensions!

What is an JAVA File Extension?

Java files are compiled versions of Java source code. The source code is written in plain text, but the file extension for java source code is “.java”. When you compile the source code, the compiler creates a “.class” file.

The “.class” file contains bytecodes, which are instructions that tell the Java Virtual Machine (JVM) how to interpret the Java program. The JVM is what actually runs your Java programs. When you run a program from the command line, the JVM loads the “.class” file and runs it.

Java files can also be run on any operating system with a Java Runtime Environment (JRE). A JRE includes a JVM and all of the other software necessary to run a Java program.

Applications of JAVA Files

JAVA files can be used to create a variety of applications. They are commonly used to create web applications, mobile applications, and desktop applications. JAVA files can also be used to create games and other types of software.

Pros and Cons of JAVA Files

When it comes to file extensions, there are a few different types of files that use the Java extension. These include:

  • Class files: Class files are compiled Java source files that contain bytecode that can be executed by the Java Virtual Machine (JVM). Class files are usually generated by the Java compiler from .java source files.
  • Java Archive (JAR) files: JAR files are compressed file archives that contain one or more class files and other resources that may be required by those classes, such as image files, property files, and so on. JAR files are used for packaging class libraries and resources into a single archive so that they can be easily deployed and run on any platform that supports Java.
  • Java source code ( .java ) files: These are the most common type of Java file; source code written in the Java programming language. The .java extension is used for all source code written in Java.

Now that we’ve looked at the different types of JAVA file extensions, let’s take a closer look at the pros and cons of each:

PROS of using JAVA Files

  • Classfiles are easy to execute since they simply need to be run through the JVM.
  • No need for special software to view or edit source codefiles.
  • Sourcefiles can be easily integrated with other applications.

CONS of using JAVA Files

  • Requires a certain level of understanding in order to work with class files.

How To Open JAVA Files?

Assuming you have the Java Runtime Environment installed on your system, most JAVA files can be opened just by double-clicking them. If that doesn’t work, try opening them with a text editor like Notepad++ or Microsoft Word. You could also try changing the file extension to .TXT and then opening it.

If that still doesn’t work, open the file with a JAR (Java Archive) opener such as 7-Zip or WinRAR.

How To Edit JAVA Files?

Assuming you have a Java file “” that looks like this:

public class Hello {

public static void main(String[] args) {

System.out.println(“Hello, world!”);



You can edit it using any text editor such as Notepad++, Sublime Text, etc. Once you’re done making your changes, save the file and then compile it using the Java compiler like this:


If there are no errors, you should now have a file called “Hello.class” which is the compiled version of your code that can be run using the Java Virtual Machine like this:

java Hello

Some Common Issues While Opening JAVA File Extensions

There are some common issues that can occur while trying to open JAVA file extensions. These include:

  • The file extension may be incorrect. Make sure that the file extension is .java and not .jav or .class.
  • The file may be corrupt. If you are receiving an error message when trying to open the file, it is likely that the file is corrupt and cannot be opened.
  • Java may not be installed on your computer. In order to open JAVA files, you must have Java installed on your system. You can download Java for free from the Oracle website.
  • Your system may not be configured to open JAVA files. Check your system’s settings to see if Java is configured to be the default program for opening .java files.

File Extension Similar To JAVA

There are a few file extensions that are similar to JAVA. These include:

  • Class Files: Class files are compiled Java programs that can be executed by the Java Virtual Machine. They have a “.class” file extension.
  • Source Code Files: Source code files contain the source code for a Java program. They have a “.java” file extension.
  • Bytecode Files: Bytecode files contain the bytecode for a Java program. They have a “.class” file extension.

Final Thoughts

When it comes to Java file extensions, there are a few different types that you might come across. The most common extension is .java, which is used for source code files.

If you want to compile a .java file into a .class file, you will need to use the javac compiler. Once you have compiled your code, you can then run it using the java command.

Another common Java file extension is .jar, which is used for JAR archives. These archives can contain many different files, such as class files, images, and other resources. You can view the contents of a JAR archive using the jar command.

Finally, there is the .class file extension, which is used for compiled Java class files. These files are not human readable and cannot be edited. If you want to view the contents of a .class file, you can use the javap command.

So there you have it! A quick overview of some of the most common Java file extensions.