Just to repeat what has been discussed some time ago.
All the current Long Term Support distributions have Java 7 available.
RHEL6, RHEL7, Ubuntu 12.04, Ubuntu 14.04 (due in April) will all have
Java 7 available.
I don't see a problem in switching to Java 7 with CloudStack 4.4 or 4.5
Wido
On 01/07/2014 12:18 AM, Kelven Yang wrote:
Java 7 has been around for some time now. I strongly suggest CloudStack to
adopt Java 7 as early as possible, the reason I feel like to raise the issue is
from the some of practicing with the new DB transaction pattern, as following
example shows. The new Transaction pattern uses anonymous class to beautify
the code structure, but in the mean time, it will introduce a couple runtime
costs
1. Anonymous class introduces a “captured context”, information exchange
between the containing context and the anonymous class implementation context
has either to go through with mutable passed-in parameter or returned result
object, in the following example, without changing basic Transaction framework,
I have to exchange through returned result with an un-typed array. This has a
few implications at run time, basically with each call of the method, it will
generate two objects to the heap. Depends on how frequently the involved method
will be called, it may introduce quite a burden to java GC process
2. Anonymous class captured context also means that there will be more
hidden classes be generated, since each appearance of the anonymous class
implementation will have a distance copy of its own as hidden class, it will
generally increase our permanent heap usage, which is already pretty huge with
current CloudStack code base.
Java 7 has a language level support to address the issues in a cheaper way that
our current DB Transaction code pattern is trying to solve.
http://docs.oracle.com/javase/tutorial/essential/exceptions/tryResourceClose.html.
So, time to adopt Java 7?
public Outcome<VirtualMachine> startVmThroughJobQueue(final String vmUuid,
final Map<VirtualMachineProfile.Param, Object> params,
final DeploymentPlan planToDeploy) {
final CallContext context = CallContext.current();
final User callingUser = context.getCallingUser();
final Account callingAccount = context.getCallingAccount();
final VMInstanceVO vm = _vmDao.findByUuid(vmUuid);
Object[] result = Transaction.execute(new
TransactionCallback<Object[]>() {
@Override
public Object[] doInTransaction(TransactionStatus status) {
VmWorkJobVO workJob = null;
_vmDao.lockRow(vm.getId(), true);
List<VmWorkJobVO> pendingWorkJobs =
_workJobDao.listPendingWorkJobs(VirtualMachine.Type.Instance,
vm.getId(), VmWorkStart.class.getName());
if (pendingWorkJobs.size() > 0) {
assert (pendingWorkJobs.size() == 1);
workJob = pendingWorkJobs.get(0);
} else {
workJob = new VmWorkJobVO(context.getContextId());
workJob.setDispatcher(VmWorkConstants.VM_WORK_JOB_DISPATCHER);
workJob.setCmd(VmWorkStart.class.getName());
workJob.setAccountId(callingAccount.getId());
workJob.setUserId(callingUser.getId());
workJob.setStep(VmWorkJobVO.Step.Starting);
workJob.setVmType(vm.getType());
workJob.setVmInstanceId(vm.getId());
workJob.setRelated(AsyncJobExecutionContext.getOriginJobContextId());
// save work context info (there are some duplications)
VmWorkStart workInfo = new
VmWorkStart(callingUser.getId(), callingAccount.getId(), vm.getId(),
VirtualMachineManagerImpl.VM_WORK_JOB_HANDLER);
workInfo.setPlan(planToDeploy);
workInfo.setParams(params);
workJob.setCmdInfo(VmWorkSerializer.serialize(workInfo));
_jobMgr.submitAsyncJob(workJob,
VmWorkConstants.VM_WORK_QUEUE, vm.getId());
}
return new Object[] {workJob, new Long(workJob.getId())};
}
});
final long jobId = (Long)result[1];
AsyncJobExecutionContext.getCurrentExecutionContext().joinJob(jobId);
return new VmStateSyncOutcome((VmWorkJobVO)result[0],
VirtualMachine.PowerState.PowerOn, vm.getId(), null);
}
Kelven
