Heap Analysis Tool 1.1 (HAT)

The Heap Analysis Tool (HAT) helps to debug unnecessary object retention (sometimes called "memory leaks") by providing a convenient means to browse the object topology in a heap snapshot, which is generated by the Java VM. HAT reads a hprof file, then sets itself up as a web server--therefore allowing you to run queries against a heap dump contained within the hprof file. A complete description of the capabilities of the tool is given in the README file.

Note: This is not a product. The Heap Analysis Tool is part of a research and development project and is being released as interesting, but unsupported, technology that may be of use as a debugging aid for Java developers.


To install, pick a directory where you'd like to install hat, and unzip the zip file (either hat_bin.zip or hat_src.zip). There's a bin directory that contains a shell script and a batch file for launching; you might want to copy these where you install software on your system. I use ~/bin on my Mac and c:/bin on PCs. You might need to edit the startup script to point to the hat.jar file that contains the program binary.


A little utility called "NetDumper" lets you grab a heap dump from a remote JVM. It's described here.

More Information

To find out more about this software, read: