Cracking Java programs part 1 by CodeRipper / SND

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Cracking Java programs part 1 by CodeRipper / SND

Cracking Java programs Part1:
In this tutorial I've posted links to homepage of some JAVA obfuscators and java to exe convertors, you may use these programs to protect some jars and see what these protections do.

Before you start take a look at these:
1. Java Virtual Machine:
http://en.wikipedia.org/wiki/Java_Virtual_Machine
2. JAVA Byte Code:
http://en.wikibooks.org/wiki/Java_Programming/Byte_Code
(also included in the tutorial archive)

Contents:
1. JAR archive
1.1 Digitally signed JAR archives
1.2 How a jar archive can be executed?
1.3 Get a jar archive from an exe

2. Java classes (.class extension)
2.1 Decompiling java classes
2.2 Finding dependencies between classes
2.3 Many jar archives - how we find in which one is a class?
2.4 ProGuard Java Obfuscator

3. Cracking java programs
3.1 JAVA opcodes (most important of them)
3.1 Finding the check after strings
3.2 Most important JAVA APIs, these also can be used for finding the check

JAVA decompilers/editors:

Online decompiler http://www.reversed-java.com/fernflower/

Class Construction Kit http://bcel.sourceforge.net/cck.html

Java Bytecode Editor http://www.cs.ioc.ee/~ando/jbe/

JD-GUI http://java.decompiler.free.fr/

DJ Java Decompiler http://members.fortunecity.com/neshkov/dj.html

Pf-cda - the best Class Dependency Analyzer  http://www.dependency-analyzer.org/

JarAnalyzer and JARDepend - display depedendeces betwen jar archives
http://www.kirkk.com/main/Main/JarAnalyzer
http://sourceforge.net/projects/jardepend/

ClassFinder - find a class after his name under jar archives
http://www.xigole.com/software/classfinder.jsp

jarcheck - display version of java classes
http://www.softpedia.com/get/Programming/Other-Programming-Files/JarCheck.shtml

retroweaver - convert classes to version 1.2,1.3,1.4
http://retroweaver.sourceforge.net/