The exception:

java.lang.reflect.InvocationTargetException

        at sun.reflect.GeneratedMethodAccessor6.invoke(Unknown Source)

        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)

        at java.lang.reflect.Method.invoke(Method.java:597)

        at org.drools.lang.RuleParserTest.execTreeParser(RuleParserTest.java:4071)

        at org.drools.lang.RuleParserTest.newParser(RuleParserTest.java:4038)

        at org.drools.lang.RuleParserTest.parse(RuleParserTest.java:3996)

        at org.drools.lang.RuleParserTest.parseResource(RuleParserTest.java:4025)

        at org.drools.lang.RuleParserTest.testTypeDeclaration1(RuleParserTest.java:3762)

Caused by: java.lang.NullPointerException

        at org.drools.lang.descr.DescrFactory.createTypeField(DescrFactory.java:401)

        at org.drools.lang.DescrBuilderTree.decl_field(DescrBuilderTree.java:1758)

        at org.drools.lang.DescrBuilderTree.type_declaration(DescrBuilderTree.java:1592)

        at org.drools.lang.DescrBuilderTree.statement(DescrBuilderTree.java:575)

        at org.drools.lang.DescrBuilderTree.compilation_unit(DescrBuilderTree.java:222)

        ... 34 more

Here is the drl that causes it:

[declare_type_1.drl]

package org.drools;

declare NetworkNode

            locElevation: java.math.BigDecimal

            name: String @key

            nodeClass: String

            locLongitude: java.math.BigDecimal

            nodeType: String

            locLatitude: java.math.BigDecimal

end

declare NetworkConnection

            id: String @key

            node1: NetworkNode

            node2: NetworkNode

            hops: Integer

end

declare NetworkEvent

            @role( event )

            @timestamp( creationTime )

            id: String @key

            locElevation: java.math.BigDecimal

            description: String

            sourceComponent: NetworkNode

            locLongitude: java.math.BigDecimal

            severity: Integer

            creationTime: java.util.Date

            locLatitude: java.math.BigDecimal

end

the test function in RuleParserTest.java you can use to replicate:

    public void testTypeDeclaration1() throws Exception {

        parseResource( "compilation_unit",

                       "compilation_unit",

                       "declare_type_1.drl" );

        final PackageDescr pack = walker.getPackageDescr();

        final List<TypeDeclarationDescr> declarations = pack.getTypeDeclarations();

        assertEquals( 3,

                      declarations.size() );

    }

I believe @key is the cause, I based my code on the example from the documentation:

declare Person

    @author( Bob )

    @dateOfCreation( 01-Feb-2009 )

    name : String @key @maxLength( 30 )

    dateOfBirth : Date

    address : Address

end

Regards

--zoly