Incremental build failure due to class loading problem.

I'm frequently seeing JNode build failures when I do an incremental build using './build.sh cd-x86-lite'. The problem goes away when I run './build.sh clean ; ./build.sh cd-x86-lite', only to recur later on. This is happening often enough to be a real nuisance.

(I should note that I always do a 'clean' build after checking out changes from SVN ... so this is not "that" problem. And it is not the "too many files open" problem.)

Here is the stacktrace:

BUILD FAILED
java.lang.NoClassDefFoundError: org/jnode/plugin/model/PluginJar
        at java.lang.ClassLoader.defineClass1(Native Method)
        at java.lang.ClassLoader.defineClass(ClassLoader.java:620)
        at org.apache.tools.ant.AntClassLoader.defineClassFromData(AntClassLoader.java:1146)
        at org.apache.tools.ant.AntClassLoader.getClassFromStream(AntClassLoader.java:1324)
        at org.apache.tools.ant.AntClassLoader.findClassInComponents(AntClassLoader.java:1388)
        at org.apache.tools.ant.AntClassLoader.findClass(AntClassLoader.java:1341)
        at org.apache.tools.ant.AntClassLoader.loadClass(AntClassLoader.java:1088)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:251)
        at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:319)
        at org.jnode.build.InitJarBuilder.execute(InitJarBuilder.java:111)
        at org.jnode.build.InitJarsBuilder.execute(InitJarsBuilder.java:83)
        at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:288)
        at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:106)
        at org.apache.tools.ant.Task.perform(Task.java:348)
        at org.apache.tools.ant.Target.execute(Target.java:357)
        at org.apache.tools.ant.Target.performTasks(Target.java:385)
        at org.apache.tools.ant.Project.executeSortedTargets(Project.java:1337)
        at org.apache.tools.ant.Project.executeTarget(Project.java:1306)
        at org.apache.tools.ant.helper.DefaultExecutor.executeTargets(DefaultExecutor.java:41)
        at org.apache.tools.ant.Project.executeTargets(Project.java:1189)
        at org.apache.tools.ant.Main.runBuild(Main.java:758)
        at org.apache.tools.ant.Main.startAnt(Main.java:217)
        at org.apache.tools.ant.launch.Launcher.run(Launcher.java:257)
        at org.apache.tools.ant.launch.Launcher.main(Launcher.java:104)
Caused by: java.lang.ClassNotFoundException: org.jnode.plugin.model.PluginJar
        at org.apache.tools.ant.AntClassLoader.findClassInComponents(AntClassLoader.java:1400)
        at org.apache.tools.ant.AntClassLoader.findClass(AntClassLoader.java:1341)
        at org.apache.tools.ant.AntClassLoader.loadClass(AntClassLoader.java:1088)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:251)
        at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:319)
        ... 27 more