JEP 241: Remove the jhat Tool

OwnerStaffan Larsen
Created2014/09/24 14:28
Updated2016/09/06 17:22
TypeFeature
StatusClosed / Delivered
Componentcore-svc / tools
ScopeJDK
Discussionserviceability dash dev at openjdk dot java dot net
EffortXS
DurationXS
Priority2
Reviewed byMikael Vidstedt
Endorsed byMikael Vidstedt
Release9
Issue8059039

Summary

Remove the antiquated jhat tool.

Motivation

jhat was added in JDK 6, based upon the java.net HAT project. jhat is an experimental, unsupported, and out-of-date tool. Superior heap visualizers and analyzers have now been available for many years.

Description

Stop building and shipping the jhat tool in the JDK.

Document this change in the appropriate release notes. Very few people are using this tool, so the impact on users should be minimal. The tool has long been marked for removal in the documentation with the words:

NOTE: This tool is experimental and may not be available in future versions of the JDK.

Testing

Existing jhat tests will need to be removed.

Some existing tests for hprof file creation use jhat to validate the files. We'll need to preserve the jhat hprof file parser/validator for use in these tests. That does not mean, however, that the code has to be in the product, rather it should be part of the tests.