NullPointerException in BaseClassFieldReader.writeExternal() when a global method is used in LHS and serialize package

Platform JIRA for DROOLS-2517

Under the conditions:

• A rule uses a method of global variable in LHS. e.g. Person(myUtil.transform(name) == "John-san")
• A package is serialized
  Serializing the package throws NullPointerException.

  java.lang.NullPointerException: null

  at org.drools.core.base.BaseClassFieldReader.writeExternal(BaseClassFieldReader.java:196)

  at org.drools.core.base.extractors.MVELObjectClassFieldReader.writeExternal(MVELObjectClassFieldReader.java:72)

  at java.io.ObjectOutputStream.writeExternalData(ObjectOutputStream.java:1459)

  at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1430)

  at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1178)

  at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:348)

  at org.drools.core.base.ClassFieldAccessorStore$FieldLookupEntry.writeExternal(ClassFieldAccessorStore.java:384)

  at java.io.ObjectOutputStream.writeExternalData(ObjectOutputStream.java:1459)

  at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1430)

  at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1178)

  at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:348)

  at java.util.concurrent.ConcurrentHashMap.writeObject(ConcurrentHashMap.java:1413)

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

  at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

  at java.lang.reflect.Method.invoke(Method.java:497)

  at java.io.ObjectStreamClass.invokeWriteObject(ObjectStreamClass.java:1028)

  at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1496)

  at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1432)

  at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1178)

  at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:348)

  at org.drools.core.base.ClassFieldAccessorStore.writeExternal(ClassFieldAccessorStore.java:61)

  at java.io.ObjectOutputStream.writeExternalData(ObjectOutputStream.java:1459)

  at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1430)

  at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1178)

  at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:348)

  at org.drools.core.definitions.impl.KnowledgePackageImpl.writeExternal(KnowledgePackageImpl.java:250)

  at java.io.ObjectOutputStream.writeExternalData(ObjectOutputStream.java:1459)

  at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1430)

  at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1178)

  at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:348)

  at java.util.ArrayList.writeObject(ArrayList.java:762)

  at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

  at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)

  at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

  at java.lang.reflect.Method.invoke(Method.java:497)

  at java.io.ObjectStreamClass.invokeWriteObject(ObjectStreamClass.java:1028)

  at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1496)

  at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1432)

  at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1178)

  at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:348)

  at org.drools.compiler.integrationtests.SerializedPackageMergeTest.testBuildAndSerializePackagesWithGlobalMethodInLHS(SerializedPackageMergeTest.java:244)