JEP 240: Remove the JVM TI hprof Agent
|Status||Closed / Delivered|
|Component||core-svc / tools|
|Discussion||serviceability dash dev at openjdk dot java dot net|
|Reviewed by||Mikael Vidstedt|
|Endorsed by||Mikael Vidstedt|
hprof agent from the JDK.
The ability to create heap dumps in the
hprof format will remain.
The useful features of the
hprof agent have been superseded by better
Heap dumps (heap=dump)
This functionality has been superseded by the same functionality in the
JVM. Using the Diagnostic Command
jcmd <pid> GC.heap_dump) it is possible to ask the JVM to dump the heap in the
hprof file format (this is also available via
Allocation profiler (heap=sites)
The Java VisualVM tool provides the same functionality, as do a number of third-party profilers.
CPU profiler (cpu=samples, cpu=times)
The CPU profiler has a couple of shortcomings which are described in some detail in http://www.brendangregg.com/blog/2014-06-09/java-cpu-sampling-using-hprof.html and elsewhere. There are other tools that provide better functionality with fewer problems. Among them are Java VisualVM and Java Flight Recorder, which are bundled with the JDK, as well as a number of third-party profilers.
hprof agent was written as demonstration code for the JVM Tool
Interface and not intended to be a production tool. The code and
documentation contain a number of statements of the following form:
This is demonstration code for the JVM TI interface and use of BCI, it is not an official product or formal part of the JDK.
Stop building and shipping the
hprof agent library (
part of the JDK.
Move the code to a separate project under OpenJDK. The code is still valuable as a demonstration of the capabilities of JVM TI, but it does not live up to the requirements for a shipping product.
The change should to be documented in the appropriate release notes.
Considering the extensive disclaimers already present in the
documentation, users should not be surprised that
hprof is being
removed, but the documentation should be updated to point to alternative
hprof agent tests will need to be removed.