XJCTask is failing with NPE when called from ANT task. The stack trace example:
value variable passed in to setProperty is null. 
/root/tiberio/test/build.xml:18: java.lang.NullPointerException 
at org.apache.tools.ant.Task.perform(Task.java:373) 
at org.apache.tools.ant.Target.execute(Target.java:341) 
at org.apache.tools.ant.Target.performTasks(Target.java:369) 
at org.apache.tools.ant.Project.executeSortedTargets(Project.java:1216) 
at org.apache.tools.ant.Project.executeTarget(Project.java:1185) 
at 
org.apache.tools.ant.helper.DefaultExecutor.executeTargets(DefaultExecutor.jav 

a:40) 
at org.apache.tools.ant.Project.executeTargets(Project.java:1068) 
at org.apache.tools.ant.Main.runBuild(Main.java:668) 
at org.apache.tools.ant.Main.startAnt(Main.java:187) 
at org.apache.tools.ant.launch.Launcher.run(Launcher.java:246) 
at org.apache.tools.ant.launch.Launcher.main(Launcher.java:67) 
Caused by: java.lang.NullPointerException 
at 
com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.setProp 

erty(XMLDocumentFragmentScannerImpl.java:776) 
at 
com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.setProperty(XML 

DocumentScannerImpl.java:448) 
at 
com.sun.org.apache.xerces.internal.impl.xs.opti.SchemaParsingConfig.setPropert 

y(SchemaParsingConfig.java:492) 
at 
com.sun.org.apache.xerces.internal.impl.xs.opti.SchemaDOMParser.setProperty(Sc 

hemaDOMParser.java:503) 
at 
com.sun.org.apache.xerces.internal.impl.xs.traversers.XSDHandler.reset(XSDHand 

ler.java:3594) 
at 
com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaLoader.reset(XMLSchemaLoad 

er.java:1068) 
at 
com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaLoader.loadGrammar(XMLSche 

maLoader.java:561) 
at 
com.sun.org.apache.xerces.internal.parsers.XMLGrammarPreparser.preparseGrammar 

(XMLGrammarPreparser.java:205) 
at 
com.sun.tools.xjc.reader.xmlschema.parser.SchemaConstraintChecker.check(Schema 

ConstraintChecker.java:78) 
at com.sun.tools.xjc.GrammarLoader.loadXMLSchema(GrammarLoader.java:330) 
at com.sun.tools.xjc.GrammarLoader.load(GrammarLoader.java:127) 
at com.sun.tools.xjc.GrammarLoader.load(GrammarLoader.java:76) 
at com.sun.tools.xjc.XJCTask._doXJC(XJCTask.java:358) 
at com.sun.tools.xjc.XJCTask.doXJC(XJCTask.java:307) 
at com.sun.tools.xjc.XJCTask.execute(XJCTask.java:247) 
at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:275) 
at org.apache.tools.ant.Task.perform(Task.java:364) 
... 10 more