JarScan is a program included in the JITWatch source tree that statically analyses a jar file and counts the bytes in each method's bytecode.

It produces a CSV format report of the class, method signature, and bytecode size for each method that is above the 325 byte threshold for inlining hot methods (-XX:FreqInlineSize=n).

This report can be used to find methods that the HotSpot JIT compiler considers "hot" but were too big to be inlined into their caller. This information can be used to refactor hot methods into smaller sub-units of code that could potentially be inlined for greater performance.

The JarScan tool is launched via the included shell script jarScan.sh