Hi,<br><br>We see the below in Guvnor from to time thrown from MapBackedClassLoader&#39;s static initialization block:-<br><br>Any ideas or thoughts? We haven&#39;t had any users report the problem but it does make a mess of our Hudson build ;)<br>
<br>Cheers,<br><br>Mike<br><pre>java.lang.ExceptionInInitializerError
	at org.drools.guvnor.server.builder.ClassLoaderBuilder$1.run(ClassLoaderBuilder.java:104)
	at org.drools.guvnor.server.builder.ClassLoaderBuilder$1.run(ClassLoaderBuilder.java:102)
	at java.security.AccessController.doPrivileged(Native Method)
	at org.drools.guvnor.server.builder.ClassLoaderBuilder.getMapBackedClassLoader(ClassLoaderBuilder.java:102)
	at org.drools.guvnor.server.builder.ClassLoaderBuilder.buildClassLoader(ClassLoaderBuilder.java:74)
	at org.drools.guvnor.server.builder.BRMSPackageBuilder.&lt;init&gt;(BRMSPackageBuilder.java:67)
	at org.drools.guvnor.server.builder.PackageAssemblerBase.createBuilder(PackageAssemblerBase.java:44)
	at org.drools.guvnor.server.builder.AssetItemValidator$BuilderValidator.init(AssetItemValidator.java:52)
	at org.drools.guvnor.server.builder.AssetItemValidator.validate(AssetItemValidator.java:43)
	at org.drools.guvnor.server.builder.drools.AssetItemValidatorTest.runValidate(AssetItemValidatorTest.java:185)
	at org.drools.guvnor.server.builder.drools.AssetItemValidatorTest.verifyValidate(AssetItemValidatorTest.java:176)
	at org.drools.guvnor.server.builder.drools.AssetItemValidatorTest.testValidate(AssetItemValidatorTest.java:159)
	at org.drools.guvnor.server.builder.drools.AssetItemValidatorTest.testValidateBRL(AssetItemValidatorTest.java:63)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:597)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:45)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:42)
	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
	at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:263)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:68)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:47)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:231)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:60)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:229)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:50)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:222)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:300)
	at org.apache.maven.surefire.junit4.JUnit4TestSet.execute(JUnit4TestSet.java:59)
	at org.apache.maven.surefire.suite.AbstractDirectoryTestSuite.executeTestSet(AbstractDirectoryTestSuite.java:120)
	at org.apache.maven.surefire.suite.AbstractDirectoryTestSuite.execute(AbstractDirectoryTestSuite.java:103)
	at org.apache.maven.surefire.Surefire.run(Surefire.java:169)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:597)
	at org.apache.maven.surefire.booter.SurefireBooter.runSuitesInProcess(SurefireBooter.java:350)
	at org.apache.maven.surefire.booter.SurefireBooter.main(SurefireBooter.java:1021)
Caused by: java.lang.NullPointerException
	at java.util.jar.Manifest$FastInputStream.fill(Manifest.java:422)
	at java.util.jar.Manifest$FastInputStream.readLine(Manifest.java:358)
	at java.util.jar.Manifest$FastInputStream.readLine(Manifest.java:390)
	at java.util.jar.Attributes.read(Attributes.java:359)
	at java.util.jar.Manifest.read(Manifest.java:182)
	at java.util.jar.Manifest.&lt;init&gt;(Manifest.java:52)
	at java.util.jar.JarFile.getManifestFromReference(JarFile.java:167)
	at java.util.jar.JarFile.getManifest(JarFile.java:148)
	at sun.misc.URLClassPath$JarLoader$2.getManifest(URLClassPath.java:696)
	at java.net.URLClassLoader.defineClass(URLClassLoader.java:228)
	at java.net.URLClassLoader.access$000(URLClassLoader.java:58)
	at java.net.URLClassLoader$1.run(URLClassLoader.java:197)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
	at org.drools.rule.MapBackedClassLoader.&lt;clinit&gt;(MapBackedClassLoader.java:38)</pre><br>