Memory Analyzer 1.14.0 Release Version: 1. After that, we simply need to get an instance of a HotSpotDiagnosticMXBean, and call its dumpHeap method. Learning Objectives Download the Eclipse Memory Analyzer: cd curl -O. To install the Memory Analyzer into an Eclipse IDE use the update site URL provided below. To do this, we first need to get an MBeanServer instance in order to get an MBean that's registered in the application. The other way to use the HotSpotDiagnostic MBean is by invoking it programmatically from Java code. We can find more information about MBeans and JMX in this article. To do this, we can use JConsole and set the HeapDumpOnOutOfMemoryError VM option to true: Therefore, it's highly recommended to always use this option, especially in production.įinally, this option can also be specified at runtime by using the HotSpotDiagnostic MBean. In the above example, it was written to the java_pid12587.hprof file.Īs we can see, this option is very useful, and there's no overhead when running an application with this option. : Requested array size exceeds VM limitĪt .main(App.java:7) When our application runs out of memory using this option, we'll be able to find the created file that contains the heap dump in the logs: : Requested array size exceeds VM limitĮxception in thread 'main' Heap dump file created

On Mac OS X, this can be done by editing MemoryAnalyzer.app/Contents/MacOS/MemoryAnalyzer.ini and increasing the value “-Xmx1024m” until it’s high enough to open the file.Java -XX:+HeapDumpOnOutOfMemoryError -XX:HeapDumpPath= If so, you will need to increase the memory allocated to MAT. When you attempt to open it you may see something like “An internal error occurred during: “Parsing heap dump from ‘/tmp/heapdumps/gf.’”. usr/java7/bin/jmap -dump:format=b,file=gf. /usr/java7/bin/java gf.core.13849Ī file of this size may not “just work” in MAT.

Please note that this operation took almost 90 minutes: Using gf.core.13849 as example of the original 33 GB file, here is how you could convert it into a 26 GB gf. file. If the heap dump provided to you was created with gcore (such as with gcore -o /tmp/gf.core $glassfish_pid) rather than jmap, you will need to convert the file before you can open it in MAT.

The Memory Analyzer Tool (MAT) from Eclipse can help you analyze heap dumps, showing you “leak suspects” such as seen at

Download eclipse memory analyzer