MetaDataManager#getMetaDataForImplementationOfReference uses the following code to load classes by name:
Class cls = referenceClass.getClassLoader().loadClass(class_name);
In some environments, like OSGi, referenceClass.getClassLoader() may return null if referenceClass was loaded by the bootstrap class loader. This may be the case if referenceClass is java.util.Set or another collection interface.
The resulting NullPointerException is swallowed by the surrounding try/catch statement and does not seem to result in any defect. This does however mean that a NullPointerException is thrown and caught for each iteration over the classMetaDataByClass keyset, resulting in a performance penalty.
This may be improved by checking if referenceClass.getClassLoader() is null before iterating over the classMetaDataByClass keyset and returning null immediately if it is the case.