Minor Description
For elements and attributes without namespace, getNamespace() may return two different values: null or an OMNamespace instance that has both prefix and namespaceURI properties set to the empty string. The value that is actually returned in this case depends in subtle ways on how the information item was created. This can be illustrated by the following code snippet:
OMElement element1 = AXIOMUtil.stringToOM("<root/>");
System.out.println(element1.getNamespace());
OMElement element2 = AXIOMUtil.stringToOM("<root xmlns=''/>");
System.out.println(element2.getNamespace());
The output is:
null
org.apache.axiom.om.impl.common.OMNamespaceImpl@0
One can see that although the two elements are equivalent, the return value of getNamespace() is different.
The return value of getNamespace() should be normalized such that it is always the same (i.e. null) for information items without namespace.