Reverse jar files

Viewed 9k times. Improve this question. I might not understand what you are asking, but isn't JBE or Krakatau is what you are looking for? Also this and this. DominikAntal The last link you gave me explains what I wanted to know. Make this an answer to get your point. Add a comment. Active Oldest Votes. Improve this answer. Dominik Antal Dominik Antal 1, 17 17 silver badges 37 37 bronze badges.

Any Linux alternative to JBE? Not sure, check out these tools. Antimony Antimony 1, 9 9 silver badges 13 13 bronze badges. Sign up or log in Sign up using Google.

Sign up using Facebook. Sign up using Email and Password. It uses therefore another mecanism and then merge both inside a single model.

The imported jar files are now at the root of your project. Note that you should not import the jar files at the root of the src. A jar could not be considered as a java src code because you can not change and manipulate directly the code.

Package Diagram reverse 2. If you look at the Package Explorer then you only see two packages javax. So I decided to investigate what is tagext package and its classifiers.

I don't see these classes in my jar file :- So my investigation is to click on BodyTag Interface and have a look where this interface is in the Package Explorer Then I realize that this interface is in another jar file :- This example helps to show that the reverse of Package using a Structural view is important in order to understand the project logic and extend jar classifiers.

Is java class file or jar file is easy to reverse engineer? Because java generates a class file after compilation and not exe files. If it is easy, then how can we protect java code so that it is difficult to reverse engineer? Yes, Java class files are easy to reverse engineer. The format is very regular, and very constrained: the VM must be able to verify that the code complies to the strong typing rules of Java code.

This is like the output of a C compiler with all optimizations deactivated: the program structure is plainly visible. People try obfuscation, though; e. For instance, all classes and methods are renamed with strings which make no sense to a human but the obfuscation also produces a translation file which the developer keeps for himself, so that he may interpret back stack traces in case of bug reports. As a rule, reverse engineering tends to work, and for Java even more so, even after obfuscation.

You'd better not use obfuscation as the foundation of your security. It is also worth noting that this is very similar to code reading issues in any. Net language such as C.

It is pretty much equally trivial to generate Java, VB. Net or C code from the distributed files and obfuscation techniques that try to make it more difficult to read are similar for both as well. There are a number of tools that allow for decompilation of java programs, and they're fairly straightforward to use.

If someone wants to modify code in an application that they have access to, that's relatively straightforward and well documented for example this McAfee paper walks through the process of decompiling a program, modifying a Java Class and then re-compiling the program. If you let someone download a copy of a program you need to assume that an attacker would be able to get access to any information within the program and can bypass any security check that is only in place on the client-side.