Memory Leaks: A Primer

from http://www.toptal.com/java/hunting-memory-leaks-in-java

For starters, think of memory leakage as a disease and Java’s OutOfMemoryError (OOM, for brevity) as a symptom. But as with any disease, not all OOMs necessarily imply memory leaks: an OOM can occur due to the generation of a large number of local variables or other such events. On the other hand, not all memory leaks necessarily manifest themselves as OOMs, especially in the case of desktop applications or client applications (which aren’t run for very long without restarts).

Think of memory leakage as a disease and the OutOfMemoryError as a symptom. But not all OutOfMemoryErrors imply memory leaks, and not all memory leaks manifest themselves as OutOfMemoryErrors.