Details
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Bug
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Status: Open
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Critical
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Resolution: Unresolved
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1.5.1, 1.5.4
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None
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None
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Microsoft Windows XP (32-bit), IBM JDK 6.0SR8FP1 (also with IBM JDK 1.5.0SR9)
Description
The issue below prevents migration to the IBM jdk and breaks build production as there are methods missing from the generated code. The problem is not a simple difference (as, for example, random placement of methods inside classes would be acceptable) but the fact that there are methods missing and conditional statements missing from generated files seemingly at random. The files that are affected appear to also be random across different runs (i.e. usually the same file does not consistently lack methods).
After investigation the issue appeared to originate from Axis2/WS Common XmlSchema. The problem does appear to be in the Apache ws-commons code or a combination of that and the way the Axis2 code uses the ws-commons code.
The org.apache.axis2.schema.SchemaCompiler class has a field named processedAnonymousComplexTypesMap, which is a HashMap whose keys are instances of org.apache.ws.commons.schema.XmlSchemaElement. That is, an anonymous complex types is looked up using the schema element that contains it.
I believe the problem is that XmlSchemaElement inherits its equals(Object) method from the XmlSchemaObject class. That equals method compares the sourceURIs, the line numbers and line positions of
the two objects. However, in the Axis2 usage, it seems that the sourceURIs are always null, and the line numbers and line positions are always zero, so the XmlSchemaObject.equals method always returns true in the Axis2 usage.
On occasion the hashCode() of two XmlSchemaElement instances is equal. Duplicate values are somewhat rare, but they do happen, apparently randomly. When the hashCode() values of two XmlSchemaElement instances are the same, and they both contain anonymous complex types, the first is entered into the processedAnonymousComplexTypesMap HashMap using the
first XmlSchemaElement as the key. The second XmlSchemaElement is subsequently used as a key in entering the second anonymous complex type. Because the hashCode() values are equal, the HashMap finds that there is already a key with the same hashCode(), so it calls the equals(Object) method to see whether the two keys are equal. The equals method returns true, so the second anonymous complex type is stored as the value associated with the first XmlSchemaElement.
We suspect that the SUN JDK just has a different hashing algorithm. It is not required to produce distinct hash codes for distinct objects as the java.lang.Object documentation
for the hashCode method states:
It is not required that if two objects are unequal according to the equals(java.lang.Object) method, then calling the hashCode method on each of the two objects must produce distinct integer results.
For each axis2 object to be treated distinctly, an IdentityHashMap must be used.
Workaround:
Modify the Apache WS Commons XmlSchemaElement class overwriting the hashCode method.
private static int counter = 1;
private int hashCode = -1;
public int hashCode() {
if (hashCode == -1)
return hashCode;
}