StringBuilder sb = new StringBuilder();
ConcurrentHashMap m = (ConcurrentHashMap) currentLockHolders.get(file);
if (m == null) {
return "(NULL)";
}
Enumeration threads = m.keys();
while (threads.hasMoreElements()) {
Thread t = (Thread) threads.nextElement();
sb.append(t.toString());
if (threads.hasMoreElements()) {
sb.append(", ");