ConcurrentModificationException thrown from JavaDocBuilder.search();

In JavaDocBuilderTest....

public void testAllowsClassInterfacesToBeCheckedInSearchBlock() {
// setup
builder.addSource(new StringReader("class Y implements SomeInterface { }"));
// execute
List results = javaDocBuilder.search(new Searcher() {
public boolean eval(JavaClass javaClass)

});
// assert
assertEquals(1, results.size());
}

Current result is this:

java.util.ConcurrentModificationException
at java.util.TreeMap$EntryIterator.nextEntry(TreeMap.java:1022)
at java.util.TreeMap$KeyIterator.next(TreeMap.java:1047)
at java.util.Collections$1.next(Collections.java:992)
at com.thoughtworks.qdox.JavaDocBuilder.search(JavaDocBuilder.java:378)