CODEWITHSUNDEEP
javajaxb
oshai
oshai

Reputation: 15355

How can I debug this NullPointerException

I have an error when unmarshaling XML to Java object with JAXB:

java.lang.NullPointerException
    at com.sun.xml.internal.bind.v2.model.impl.RuntimeBuiltinLeafInfoImpl$1.parse(RuntimeBuiltinLeafInfoImpl.java:188)
    at com.sun.xml.internal.bind.v2.model.impl.RuntimeBuiltinLeafInfoImpl$1.parse(RuntimeBuiltinLeafInfoImpl.java:186)
    at com.sun.xml.internal.bind.v2.runtime.reflect.TransducedAccessor$CompositeTransducedAccessorImpl.parse(TransducedAccessor.java:230)
    at com.sun.xml.internal.bind.v2.runtime.unmarshaller.LeafPropertyLoader.text(LeafPropertyLoader.java:50)
    at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallingContext.text(UnmarshallingContext.java:483)
    at com.sun.xml.internal.bind.v2.runtime.unmarshaller.InterningXmlVisitor.text(InterningXmlVisitor.java:78)
    at com.sun.xml.internal.bind.v2.runtime.unmarshaller.StAXEventConnector.handleCharacters(StAXEventConnector.java:173)
    at com.sun.xml.internal.bind.v2.runtime.unmarshaller.StAXEventConnector.bridge(StAXEventConnector.java:127)
    at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallerImpl.unmarshal0(UnmarshallerImpl.java:392)
    at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallerImpl.unmarshal(UnmarshallerImpl.java:368)

How can I find the cause?

some more details:

part of the xml that I am trying to parse is:

<member_resources>
                    <__field_location__>
                            <directive>
                                    sun-sat
                            </directive>
                            <file>
                                    null
                            </file>
                            <line>
                                    0
                            </line>
                    </__field_location__>
                    <sun-sat>
                            00:00-24:00 tester2
                    </sun-sat>
                    <__field_location__>
                            <directive>
                                    isLine
                            </directive>
                            <file>
                                    null
                            </file>
                            <line>
                                    0
                            </line>
                    </__field_location__>
                    <isLine>
                            true
                    </isLine>
            </member_resources>

when stopping at the event that caused this I get:

next event <__field_location__>
next event <directive>
next event sun-sat
next event <file>
next event null

Upvotes: 1

Views: 802

Answers (3)

Florent Guillaume
Florent Guillaume

Reputation: 8343

Add an exception breakpoint for NullPointerException. When it's hit, explore a few levels higher in the call stack to find out the state of the local variables, you'll probably get a clue as to what is null.

Upvotes: 3

Sam
Sam

Reputation: 6890

A good approach is using source of JAXB(its implementation) and a IDE for debugging.

Upvotes: 3

fdierre
fdierre

Reputation: 952

Well, a starting point could be setting a breakpoint at the call to the unmarshaler and check exactly which arguments it is being passed.

First thing I'd check is that what you're passing is actually xml, and that it is both well-formed and valid.

Upvotes: 1

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