Drools : drlDumper.dump() gives null pointer error

[sumit...@gmail.com]

I am new to drools, i am trying to create .drl from .xml rules file by using drools API. Below is the code used for conversion

 Reader source = new InputStreamReader(
            DroolsTest.class.getResourceAsStream(xmlFileName));
    XmlPackageReader xmlPackageReader = new XmlPackageReader(new SemanticModules());                
    PackageDescr pkgDesc = xmlPackageReader.read(source);
    DrlDumper drlDumper = new DrlDumper();
    String drl = drlDumper.dump(pkgDesc);
    System.out.println(drl);
    return drl;

Here is the exception stack trace

[Error: null pointer: pkg.namespace] [Near : {... @code{ ....}] ^ [Line: 1, Column: 1] at org.mvel2.optimizers.impl.refl.ReflectiveAccessorOptimizer.compileGetChain(ReflectiveAccessorOptimizer.java:427) at org.mvel2.optimizers.impl.refl.ReflectiveAccessorOptimizer.optimizeAccessor(ReflectiveAccessorOptimizer.java:140) at org.mvel2.ast.ASTNode.optimize(ASTNode.java:159) at org.mvel2.ast.ASTNode.getReducedValueAccelerated(ASTNode.java:115) at org.mvel2.MVELRuntime.execute(MVELRuntime.java:86) at org.mvel2.compiler.CompiledExpression.getDirectValue(CompiledExpression.java:123) at org.mvel2.compiler.CompiledExpression.getValue(CompiledExpression.java:119) at org.mvel2.compiler.CompiledExpression.getValue(CompiledExpression.java:113)at org.mvel2.MVEL.executeExpression(MVEL.java:930) at org.mvel2.templates.res.CompiledExpressionNode.eval(CompiledExpressionNode.java:45) at org.mvel2.templates.res.TextNode.eval(TextNode.java:42) at org.mvel2.templates.TemplateRuntime.execute(TemplateRuntime.java:285) at org.mvel2.templates.TemplateRuntime.execute(TemplateRuntime.java:247) at org.mvel2.templates.TemplateRuntime.execute(TemplateRuntime.java:255) at org.mvel2.templates.TemplateRuntime.execute(TemplateRuntime.java:207) at org.drools.compiler.lang.DrlDumper.dump(DrlDumper.java:59) at com.sample.DroolsTest.convertXmlToDrlFile(DroolsTest.java:65) at com.sample.DroolsTest.main(DroolsTest.java:34) Caused by: java.lang.NullPointerException at org.mvel2.optimizers.impl.refl.ReflectiveAccessorOptimizer.compileGetChain(ReflectiveAccessorOptimizer.java:360) ... 17 more