for (Iterator<BugInstance> i = bugCollection.iterator(); i.hasNext();) {
BugInstance warning = i.next();
MethodAnnotation method = warning.getPrimaryMethod();
if (method != null) {
MethodDescriptor methodDesc = method.toMethodDescriptor();
Collection<BugInstance> warnings = warningsByMethod.get(methodDesc);
if (warnings == null) {
warnings = new LinkedList<BugInstance>();
warningsByMethod.put(methodDesc, warnings);
}