JDK-8046092 : JEP 102: Process API Updates
  • Type: JEP
  • Component: core-libs
  • Sub-Component: java.lang
  • Priority: P2
  • Status: Closed
  • Resolution: Delivered
  • Fix Versions: 9
  • Submitted: 2011-09-01
  • Updated: 2017-03-09
  • Resolved: 2016-02-18
Related Reports
Blocks :  
JDK-8044122 - MBean access to the PID
Blocks :  
JDK-8044840 - [TESTBUG] get rid of JMX in com.oracle.java.testlibrary.ProcessTools.getProcessId() for getting current process id
Blocks :  
JDK-8077089 - JEP-JDK-8046092: Test Task: Process API Updates
Blocks :  
JDK-8077350 - JEP 102 Process API Updates Implementation
Relates :  
JDK-8066847 - jdk/test/lib/testlibrary/jdk/testlibrary/ProcessTools.java, to eliminate dependency on sun.management.VMManagement
Relates :  
JDK-8075621 - JEP 279: Improve Test-Failure Troubleshooting
Relates :  
JDK-4076796 - (process) Provide Process.isAlive(), like Thread.isAlive()
Relates :  
JDK-4890847 - (process) Add Process.ID and Process.waitFor(long timeout)
Relates :  
JDK-8003490 - (process) Provide Process.getCurrentPid() to get identifier of current process
Relates :  
JDK-8074569 - Update implementation to use ProcessHandle.current() to get the PID
Relates :  
JDK-6439432 - (process) Access to system-specific process-related APIs
Relates :  
JDK-6447323 - (process) Native OS process information and control
Relates :  
JDK-4333183 - (process) Add a way to gently shutdown, as opposed to destroy, a subprocess
Sub Tasks
JDK-8077089 :  
JEP-JDK-8046092: Test Task: Process API Updates - Closed
JDK-8169513 :  
Update with final design detail - Resolved
Description
Summary
-------

Improve the API for controlling and managing operating-system processes.


Motivation
----------

The limitations of the current API often force developers to resort to
native code.


Description
-----------

Java SE provides limited support for native operating-system processes.
It provides a basic API to setup the environment and start a process.
The process streams can, since Java SE 7, be redirected to files, pipes,
or can be inherited.  Once started, the API can be used to destroy the
process and/or wait for the process to terminate.

The java.lang.Process class is enhanced to provide the operating specific
process id of the process, information about the process including
the arguments, the command, the start time of the process, the accumulated
cpu time of the process and the user name for the process. 

The java.lang.ProcessHandle class returns information about each process
as provided by the operating system including process id, arguments, command,
start time, etc.  A ProcessHandle can return the process' parent, and the direct children,
and to all descendants via a stream of ProcessHandles.

ProcessHandles can be used to destroy processes and monitor process liveness.
With ProcessHandle.onExit, the asynchronous mechanisms of CompletableFuture
can be used to schedule an action to be taken when the process exits.

Access to information about processes and control of processes is subject to security
manager permissions and are limited by the normal operating system access controls.

Testing
-------

The classes or methods introduced will require new unit tests that can be
developed along with the implementation.  More functional tests would be
useful too.


Risks and Assumptions
---------------------

The main risk with this API is differences between operating systems, in
particular Windows.

The design of this API needs to accommodate possible deployment on
smaller devices with different operating system models.  It should also
take into account environments where multiple Java virtual machines are
running in the same operating system process.  These considerations could
lead to a more abstract API and/or increase the design effort.
Comments
The main body of the ProcessHandle implementation has been pushed in JDK-8077350 JEP 102 Process API Updates Implementation. There is some remaining work and some incrementally suggested enhancements.
15-06-2015
Yes. Whatever new support is added in this area, please make sure that the specification allows it to be optional. There's an approved CCC request that clarifies the optionality of the existing process execution APIs for JDK 9. http://ccc.us.oracle.com/8055330
06-10-2014
Just to add that the API proposed here are expected to be added to Java SE and so would need be present in all Java SE implementations. There is separate spec clarification in progress to make it clearer that support for creating operating system will be optional (to allow for environments such as iOS). That may be what Aleksey's question is about.
03-10-2014
A feature missing from the api to query processes is information about the processes that is available from the OS. For example, cpu time, start time, user id, group id, command, arguments, working directory, memory size. The information would be provided on an as available basis with a set of known keys, but not every OS would be required to return all the information.
24-06-2014
With respect to the JEP 102 bullet: "The ability to enumerate Java virtual machines and processes on the system. Information on each process may include its pid, name, state, and maybe resource usage." The capability is not planned to be specialized for Java Virtual Machines; information common to any process would be made available. VM specific functions are already provided by serviceability in the commands jps, jcmd, etc.
24-06-2014