Hi, We see the below in Guvnor from to time thrown from MapBackedClassLoader's static initialization block:- Any ideas or thoughts? We haven't had any users report the problem but it does make a mess of our Hudson build ;) Cheers, Mike java.lang.ExceptionInInitializerError at org.drools.guvnor.server.builder.ClassLoaderBuilder$1.run(ClassLoaderBuilder.java:104) at org.drools.guvnor.server.builder.ClassLoaderBuilder$1.run(ClassLoaderBuilder.java:102) at java.security.AccessController.doPrivileged(Native Method) at org.drools.guvnor.server.builder.ClassLoaderBuilder.getMapBackedClassLoader(ClassLoaderBuilder.java:102) at org.drools.guvnor.server.builder.ClassLoaderBuilder.buildClassLoader(ClassLoaderBuilder.java:74) at org.drools.guvnor.server.builder.BRMSPackageBuilder.<init>(BRMSPackageBuilder.java:67) at org.drools.guvnor.server.builder.PackageAssemblerBase.createBuilder(PackageAssemblerBase.java:44) at org.drools.guvnor.server.builder.AssetItemValidator$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.<init>(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.<clinit>(MapBackedClassLoader.java:38)