Issue1642285

Not all, but some jar files fail to generate cache.  For example, following jar is a jar file of WebLogic 9.2:

C:\jython-2.2a1>set CLASSPATH=C:\bea\weblogic92\server\lib\webserviceclient.jar
C:\jython-2.2a1>jython.bat
*sys-package-mgr*: processing new jar, 'C:\bea\weblogic92\server\lib\webserviceclient.jar'
*sys-package-mgr*: skipping bad jar, 'C:\bea\weblogic92\server\lib\webserviceclient.jar'
Jython 2.2a1 on java1.5.0_06 (JIT: null)
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>>> _

Haven't debugged throughly, but it seems that EOFException is happening at the beginning of org.python.core.PackageManager#checkAccess() at line 166 (int magic = istream.readInt()).  So a quick fix is that let checkAccess() return -1 when the EOFException happened.  After the quick fix, I don't see the "skipping bad jar" error message anymore.

I'm not sure webserviceclient.jar is redistributable. In case you want to reproduce, please download WebLogic Platform 9.2 from BEA (http://commerce.bea.com/products/weblogicplatform/weblogic_prod_fam.jsp).

The problem occurs because webserviceclient.jar contains at least one .class file (weblogic/utils/io/ChunkManager.class) that is completely empty.  I think skipping such aberrant classes makes perfect sense, and I believe returning -1 from checkAccess will have that result, but will need to investigate a little further before I commit a fix.

Fixed in r3187 for trunk.  Fix needs to be migrated to 2.3 branch.