JCavaj Java Decompiler is a free Java-based Java Decompiler. It reconstructs the original source code from a compiled binary class file. You can decompile java applets, jar and zip files producing accurate java source code. JCavaj runs on any platform with Java Runtime Environment 1.4 or higher installed.

Cavaj Java Decompiler is a graphical freeware utility that reconstructs java source code from CLASS files. You can decompile java applets, jar and zip files producing accurate java source code. Browse the reconstructed source code with the Class View for instant access to methods and fields. Cavaj Java Decompiler is a standalone Windows application, it doesn't require you to have Java installed.

Java Launcheris contains 9 launching features
Run Java programs by double-clicking, View Java codes and class hierarchies, Display contents of jar and zip files without extracting them, Compile thousands of Java files, Execute thousands of applications and applets, Debug thousands of applications and applets by right-clicking
Create Windows exe file from Java application, Create executable (cross-platform) jar files
And Java Help System

MaintainJ, an Eclipse plug-in, generates runtime UML sequence and class diagrams for a given use case, helping the users to quickly understand a complex Java application. MaintainJ logs runtime method execution sequence to a file and uses that trace file to render sequence and class diagrams. MaintainJ Instrumentation Wizard instruments a Java/J2EE application and MaintainJ UML Editor renders sequence and class diagram from the trace file.

DJ Java Decompiler is Windows 95/98/Me/NT/2000 decompiler and disassembler for Java that reconstructs the original source code from the compiled binary CLASS files. This program can take compiled binary class files including applets, and "dead" code parts and generate accurate source code. The program also includes a full-featured Java editor that features a GUI with syntax-coloring. Enables users to save, edit and compile the generated java code

SDE for Sun ONE is an easy-to-use UML tool seamlessly integrated with Sun ONE. SDE supports full software development life-cycle - analysis, design, coding, testing and deployment. SDE supports the latest UML notation, code generation (model to Java), reverse engineering (Java to model), import/export XMI, Rational Rose...
+Visio integration
+Round-trip engineering
+Version control
+Plug-in and template support
+more

SDE for NetBeans is an easy-to-use UML tool seamlessly integrated with NetBeans. SDE supports full software development life-cycle - analysis, design, coding, testing and deployment. SDE supports the latest UML notation, code generation (model to Java), reverse engineering (Java to model), import/export XMI, Rational Rose...
+Visio integration
+Round-trip engineering
+Version control
+Plug-in and template support
+more

SDE for JDeveloper is an easy-to-use UML tool seamlessly integrated with JDeveloper. SDE supports full software development life-cycle - analysis, design, coding, testing and deployment. SDE supports the latest UML notation, code generation (model to Java), reverse engineering (Java to model), import/export XMI, Rational Rose...
+Visio integration
+Round-trip engineering
+Version control
+Plug-in and template support
+more

SDE for JBuilder is an easy-to-use UML tool seamlessly integrated with JBuilder. SDE supports full software development life-cycle - analysis, design, coding, testing and deployment. SDE supports the latest UML notation, code generation (model to Java), reverse engineering (Java to model), import/export XMI, Rational Rose...
+Visio integration
+Round-trip engineering
+Version control
+Plug-in and template support
+more

SDE for Eclipse is an easy-to-use UML tool seamlessly integrated with Eclipse. SDE supports full software development life-cycle - analysis, design, coding, testing and deployment. SDE supports the latest UML notation, code generation (model to Java), reverse engineering (Java to model), import/export XMI, Rational Rose...
+Visio integration
+Round-trip engineering
+Version control
+Plug-in and template support
+more