Summary

Remove the System Property "jmx.tabular.data.hash.map" which was introduced historically for JMX compatibility with JDK 1.3 clients.

Problem

TabularDataSupport reads a boolean System Property "jmx.tabular.data.hash.map", which can be set true to use HashMap, and not LinkedHashMap. The concern was that JDK 1.3 JMX clients would not have LinkedHashMap. This was considered unlikely at the time (as noted in the source comment), and was not documented.

This compatibility convenience flag should be removed.

Solution

Remove the code that reads the Property "jmx.tabular.data.hash.map", the conditions related to it, and update tests.

New behaviour will be the same as current behaviour with the property unset.

Specification

No specification change. Property is not documented in the JDK.

Github PR: https://github.com/openjdk/jdk/pull/23153