Visual VM makes it very easy to take a heap dump running on your local machine. The option live is important if you want to collect only the live objects i.e objects that still have a reference in the running code.

After finding the pid, run the following command.The processes will be listed in the following format “ ” You can use the jps tool to list down all the running Java processes on your local machine. Find the process id of your running Java application.These steps are common for all operating systems including Windows, Linux, and macOS. Command-line interface to generate the Heap Dump We will talk about the 3 easiest ways to do it. There are several ways to take a heap dump. How to take a Heap dump of your running Java Application In this case, you should either analyze the heap dump on the same server machine which doesn’t have memory constraint or use live memory sampling tools provided by VisualVM. Therefore, tools like MAT, Jhat won’t be able to load the heap dump file. For instance, a server may have crashed with a heap dump of size 24 GB and your local machine may only have 16 GB of memory. Usually analyzing heap dump takes even more memory than the actual heap dump size and this may be problematic if you are trying to analyze heap dump from a large server on your development machine. How do you analyze very large Heap dumps? We can also go into fine details and find out the amount of memory retained by a single Java object in the application. These details can help us pinpoint the actual code that is causing the memory leak issues.

Using the heap dump we can find details like the memory usage per class, number of objects per class, etc. Analyzing the heap dump will lead us to the root cause of the anomaly. You may need to take the Heap dump if your Java application is taking up more memory than you expected or your Java application crashed with OutOfMemoryError. Why and When should I take the Heap dump? In this post, we will see how you can take the heap dump of your running Java application and use Eclipse’s Memory Analyzer (MAT) to identify memory hotspots and possibility detect memory leak. The heap dump file is usually stored with. Heap dump analysis using Eclipse Memory Analyzer Tool (MAT)Ī heap dump is a snapshot of all the Java objects that exist in the heap space.

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