Currently the equals() method of org.compass.needle.coherence.FileLockKey does not check for null.
This causes an occasional NPE on line 62
public boolean equals(Object o) {
if (this == o) return true;
=====>if (((FileKey) o).getType() != getType()) return false;
Changing this to
public boolean equals(Object o) {
if (this == o) return true;
if(o==null) return false;
if (((FileKey) o).getType() != getType()) return false;
Fixes the problem.
(at least in my Coherence*Extend environment)