How to decompile class file in Java and Eclipse - Javap command example

To decompile a Java class file using the javap command in Eclipse, you can follow these steps:

Open a command prompt or terminal: Start by opening a command prompt or terminal on your computer.

Navigate to the directory: Use the cd command to navigate to the directory where the class file is located. For example, if your class file is in the directory C:\myproject\bin, use the following command:

bash

cd C:\myproject\bin

Decompile the class file: Once you are in the correct directory, run the javap command followed by the name of the class file you want to decompile. For example, if your class file is named MyClass.class, use the following command:

vbnet

javap MyClass

The javap command will decompile the class file and display the resulting bytecode and other information in the command prompt or terminal.

Note that the javap command is a part of the Java Development Kit (JDK), so you need to have the JDK installed on your computer and its bin directory added to your system's PATH variable for the command to work. Also, make sure that the class file you want to decompile is compiled with debugging information.

Alternatively, if you are using Eclipse, you can also use the following steps to decompile a class file:

• Open the Java Decompiler perspective: In Eclipse, go to "Window" -> "Perspective" -> "Open Perspective" -> "Other...". Select "Java Decompiler" from the list and click "OK".
• Import the class file: In the "Java Decompiler" perspective, right-click on the package or project where the class file is located and select "Import". Choose "File System" and browse to the directory containing the class file. Select the class file and click "Finish" to import it into Eclipse.
• View the decompiled code: Once the class file is imported, you can view its decompiled code by expanding the package/project in the Package Explorer or Navigator view. Double-click on the class file to open it, and the decompiled code will be displayed in the editor window.

Using either the javap command or the Java Decompiler perspective in Eclipse, you can decompile Java class files and view their bytecode or decompiled source code.