Debugging Memory Usage

OpenNMS has “-XX:+HeapDumpOnOutOfMemoryError” enabled by default, so it will create a heap dump if it runs out of memory (see That page doesn’t exist or is private - #8 by dino2gnt for more information). The “jhat” tool is no longer supported nor included in current JDKs. It looks like it has been replaced by Java VisualVM: Java VisualVM