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SmallData | Blog | Detecting a permgen memory leak in a Java JBoss application

The Permanent Generation (PermGen) Heap is a heap in the JVM dedicated to storing the JVM’s internal representation of Java Classes (and also interned String instances). Usually, this heap is of a fixed size in the JVM and if it runs out of space then an OutOfMemory exception is thrown even if there is space available in the other heaps.