Convert a .class to .java file (decompiler)Tag(s): Open Source
Jad
Jad, the fast JAva Decompiler, is a program that reads one or more Java class files and converts them into Java source files which can be compiled again.Jad is a 100% pure C++ program and it generally works several times faster than decompilers written in Java. Jad doesn't use the Java runtime for its functioning, therefore no special setup is required (like changes to the CLASSPATH variable).
Jad is not open source but it is free to use.
Make sure to download the GUI interface, FrontEnd Plus .
On Windows, a file association with the .class extension is made so if you click on a class file then the decompiled is shown in FrontEnd Plus right away.
JAD is good but out-dated, the new class format introduced with JDK1.5 is not well supported.
JadClipse
JadClipse is a plug-in that seamlessly integrates Jad (the fast Java decompiler) with Eclipse.Normally, when opening a class file the Class File Viewer will show a brief API outline of the class. If you install this plug-in, however, the Class File Viewer will be replaced with the JadClipse Class File Viewer that shows the decompiled source of the class.
http://jadclipse.sourceforge.net/wiki/index.php/Main_Page
JD - Java decompiler
The Java Decompiler project aims to develop tools in order to decompile and analyze Java 5 byte code and the later versions.JD is Open Source and free to use.
Also available is JD-GUI, a standalone graphical utility that displays Java source codes of .class files, and JD-Eclipse, a plug-in for the Eclipse platform.
http://java.decompiler.free.fr/
JarPlug
By default, the support for viewing and editing JAR file in Eclipse is very limited.With JarPlug, it is possible delete or update items stored in a JAR.
http://jar-plug.sourceforge.net/