Java Heap Analysis Tool 1.1 (HAT) HAT is a program that analyzes a heap dump file for Java programs. This tool can help a developer to debug and analyze the objects in a running Java program. It is particularly useful when debugging unintentional object retention. HAT was originally written in 1998, and was oritinally responsible for the addition of .hprof heap dump files in JVMDI in JDK 1.2. in Development > Javawith analysisanalyzerdumpdumpsheapjavajdktool