We have a tool wscompile in Application Server. wscompile tool generates some Java classes and compiles them.The generated classes use some api(let's say javax.xml.rpc.Service), which are in the classpath. The api classes are bundled in javaee.jar and j2ee.jar has reference to javaee.jar in the classpath manifest. Only j2ee.jar is set in the classpath of wscompile.
Importantly, Javac fails to compile with JDK6 U4 b03 but works fine with U4 b02 saying it cant find the api classes.

Is there any change in b03 thats causing this problem?

I will try to attach a testcase soon, I am filing this to see if you can recollect any changes in this area so that we can decide on if we should ship App Server SDK.
I am attaching a testcase to show how Wscompile tool in jaxrpc calls Javac.
Set JAVA_HOME and run "ant build" to see the issue.
By passing -DnonBatchMode, it worked.
A new standalone test is added and reproduces the problem.
If Javac is invoked multiple times, it happens