Oracle releases free tool

Java performance tool makes shock reappearance

Elliot Bentley

After two-year absence, JRockit Mission Control returns in Java 7u40 with support for HotSpot and more goodies.

JRockit’s JVM profiling
functionality has returned – and has picked up some new tricks in
its two-year absence.

Last updated
in December 2011
, but seemingly lost in Oracle’s acquisition of
JRockit creators Appeal,
Java Mission Control
is designed to help track down leaks and
performance bottlenecks.

Mission Control has had a considerable upgrade, now bundled for
free with the regular desktop release (starting with Java SE 7
update 40
) and providing support for both JRockit and HotSpot

A key feature is Flight Recorder, which (as the name suggests)
logs live data from production application for future analysis. The
performance overhead incurred is “less than 2%”, claims Marcus Hirt, who joined
Oracle when Appeal was acquired.

A new JVM Browser show sub-nodes for server side services
available and can be viewed as a flat list or a tree, while
performance-sapping code can be identified quickly using the new
method profiling and improved allocation profiling tools.

The team say they are working on introducing additional
functionality using experimental plugins such as JOverflow, a heap
dump analysis tool, and DTrace, a more detailed recording tool. Not
yet implemented, however, is JRockit Mission Control’s on-line heap
analyser Memleak – though JOverflow now encompasses much of its

Eclipse 3.8/4.2 plugin
is also now available for Mission
Control, although with a couple of caveats: the 4.2 performance
issues apparently make it very slow, and 4.3 support is still in
the works.

This week’s Java update also introduces a ‘Deployment Rule Set’
for restricting Java Web Start usage, which sysadmins who still
need to support Java on their users’ desktops may find useful, as
well as support for high-DPI ‘retina’ screens on OS X.

Photo by Ian

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