java.lang.NoClassDefFoundError on Android after changing a class file

Question

I have a jar library. I used Java Class File Editor (CE) to modify one class in this library. In this class, I changed a variable from private static final to public static. Afterwards, I put the newly modified class file into same jar library using WinRAR.

However, running the app on Android produces a NoClassDefFoundError.

How do I resolve the NoClassDefFoundError?

Please help.

http://stackoverflow.com/questions/9857539/noclassdeffounderror-when-googleanalyticstracker-getinstance/9857669#9857669 — Akram, Jun 23 '12 at 08:01

score 1 · Answer 1 · answered Jun 23 '12 at 04:45

1

One possibility is that WinRAR has created a file that is no longer JAR compatible. I'd recommend not using WinRAR. Use the jar command to unpack that JAR file into a directory tree, make the change(s), and repack it again using jar.

Another possibility is that your change has triggered a code verification problem or similar. Show us the complete error message and stacktrace for the exception?

answered Jun 23 '12 at 04:45

Stephen C

698,415
94
811
1,216

E/AndroidRuntime(6245): Caused by: java.lang.NoClassDefFoundError – jas7 Jun 23 '12 at 05:00
I tried the jar command instead of WinRAR. But I still get NoClassDefFoundError. – jas7 Jun 23 '12 at 05:01
Show us the complete stacktrace. And use `jar -t` on the updated JAR file to make sure that the class is in the right place. – Stephen C Jun 23 '12 at 06:59
How to produce a stacktrace? Do you mean the messages on Logcat? – jas7 Jun 23 '12 at 07:21

score 0 · Answer 2 · answered Jun 23 '12 at 04:37

I'm not sure if this is related or if it's entirely possible that changing the contents of a class file could've affected this, but maybe you should just try doing Project -> Clean in Eclipse. Also, do try including the jar file in the /libs folder if you haven't already.

Furthermore, confirm that your Jar file is compressed properly when you recreated it.

score 0 · Accepted Answer · answered Jun 27 '12 at 20:05

0

I think the problem is caused by RSA encryption.

answered Jun 27 '12 at 20:05

jas7

2,893
6
23
36

java.lang.NoClassDefFoundError on Android after changing a class file

3 Answers3