How to deobfuscate jar file

Hi,

Thanks in Advance

Is there is any open source tool for deobfuscation?

Not able to read the decompiled files its showing class/method as A/B/C etc

Regards
Vinoth

Why would you want to do that? If you got someone else's .jar without the source code, than you're surely not intended to see or use it.

No, that information is no longer in the class file.

You can deobfuscate an obfuscated jar file manually. Unfortunately, you need a mind of a Vulcan to do it. So, until humanity discovers space travel, gets in contact with an alien race of superior intellect, that doesn't want to exterminate us, NO!

Thanks for the quick response

@Kemal Sokolovic Got third party jar want to know whats happening
@Jayesh :-)

VinothKumar Kuttiappan wrote:
@Kemal Sokolovic Got third party jar want to know whats happening

I'd suggest you read a) their EULA and b) their documentation. Often, the EULA says that it is a violation to try and reverse engineer their code. Their documentation should tell you all you need to know.

Ulf Dittmer wrote:No, that information is no longer in the class file.

Method names (and arg types) are present in the classfiles.

It's true, the method names are in the class files. But after the obfuscator gets through with its task of renaming method "getLastPayrollPeriod" to "d", all you have in the class files is "d" and "getLastPayrollPeriod" is nowhere to be found.

fred rosenberger wrote:Their documentation should tell you all you need to know.

I think you may live in a different world than I do.

Ivan Jozsef Balazs wrote:Method names (and arg types) are present in the classfiles.

Vinoth is asking about human-comprehensible names (e.g., the original ones). In an obfuscated class, that information is not present.

Mike Simmons wrote:

fred rosenberger wrote:Their documentation should tell you all you need to know.

I think you may live in a different world than I do.

In my defense....I did say "should"...

Jayesh A Lalwani wrote:You can deobfuscate an obfuscated jar file manually. Unfortunately, you need a mind of a Vulcan to do it. So, until humanity discovers space travel, gets in contact with an alien race of superior intellect, that doesn't want to exterminate us, NO!

If you know the obfuscation tool used (e.g. ZKM), you can use byte code engineering (ASM/BCEL) to deob it (in ZKM's case, fix the flow control). If you don't know the method used, you can analyze it, and more times than not, it will be using a popular obfuscation tool.

Thanks all of you

One sample class, interested in knowing original class/method names

package android.support.v4.a;

import java.io.PrintWriter;

public final class a<D>
{
  int a;
  b<D> b;
  boolean c;
  boolean d;
  boolean e;
  boolean f;

public final void a()
  {
    this.c = true;
    this.e = false;
    this.d = false;
  }

public final void a(int paramInt, b<D> paramb)
  {
    if (this.b != null)
      throw new IllegalStateException("There is already a listener registered");
    this.b = paramb;
    this.a = paramInt;
  }

public final void a(b<D> paramb)
  {
    if (this.b == null)
      throw new IllegalStateException("No listener register");
    if (this.b != paramb)
      throw new IllegalArgumentException("Attempting to unregister the wrong listener");
    this.b = null;
  }

public final void a(String paramString, PrintWriter paramPrintWriter)
  {
    paramPrintWriter.print(paramString);
    paramPrintWriter.print("mId=");
    paramPrintWriter.print(this.a);
    paramPrintWriter.print(" mListener=");
    paramPrintWriter.println(this.b);
    paramPrintWriter.print(paramString);
    paramPrintWriter.print("mStarted=");
    paramPrintWriter.print(this.c);
    paramPrintWriter.print(" mContentChanged=");
    paramPrintWriter.print(this.f);
    paramPrintWriter.print(" mAbandoned=");
    paramPrintWriter.print(this.d);
    paramPrintWriter.print(" mReset=");
    paramPrintWriter.println(this.e);
  }

public final void b()
  {
    this.c = false;
  }

public final void c()
  {
    this.d = true;
  }

public final void d()
  {
    this.e = true;
    this.c = false;
    this.d = false;
    this.f = false;
  }

public final String toString()
  {
    StringBuilder localStringBuilder = new StringBuilder(64);
    android.support.v4.c.a.a(this, localStringBuilder);
    localStringBuilder.append(" id=");
    localStringBuilder.append(this.a);
    localStringBuilder.append("}");
    return localStringBuilder.toString();
  }
}

Again:

Ulf Dittmer wrote:No, that information is no longer in the class file.