从Android库项目引用的Jar未被App引用。 NoClassDefFoundError

Question

I have searched SO and tried all the solutions I came across but nothing seems to work. The things I tried are the solutions given here , here , here , here and here but nothing seems to work.

As described in some of those question I have a java library (lets say J) included in a android library (AL) that is included in a android app (AA). I have added the library to the libs of both (have also tried with adding it to just AA and including in AL, and vice-versa and just in AL and expecting android dependencies to take care of it) but that or anything else did not work.

I am using the latest tools(version 20.0.3). The build android version for the android library and the app is 2.2 and min SDK is 5.

I can see the the java library in the android dependencies of the app but am getting a NoClassDefFoundException and run time.

How can I get this to work?

The android library must reference a jar, since that contains some encryption logic that I need to hide. The library is being created for distribution, the app is just something quite simple for testing the library.

Answer 1

There were 2 different but related problems causing this issue.

1. The Java library, J was compiled with compliance level 1.7 (default for my system). This needs to be at 1.5, the compliance level of Android. (compliance level may change in the future).
2. The J library was also compiling using the J2SE library. I had to replace that with the anroid.jar of the same api level as my app.

Then also things didn't work and for some reason it started working after I deleted the project and recreated in new directories.(IMP: take a code backup first).