Java - Incorrect JIT optimization (suppose)

[Sławomir Domagała]

The Program creates a graph including: 20 vertex and 19 edges. Every edge can crash with probability 0.95. The aim of program is to estimate the probability of that the graph stays connected in one component. In this case the probability should be about 0.37.
If you run program you will see 0.37, but if you comment line: "System.out.println(niezawodnosc)" in method IsProper in class Krawedz, you will see 0.56 (incorrect). It looks like jre is trying to optimize method IsProper. Additionaly the last line shows the random generator works well.

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: openjdk-6-jre 6b31-1.13.3-1ubuntu1
ProcVersionSignature: Ubuntu 3.13.0-24.46-generic 3.13.9
Uname: Linux 3.13.0-24-generic x86_64
ApportVersion: 2.14.1-0ubuntu3
Architecture: amd64
CurrentDesktop: Unity
Date: Tue Apr 29 18:41:17 2014
DistributionChannelDescriptor:
 # This is a distribution channel descriptor
 # For more information see http://wiki.ubuntu.com/DistributionChannelDescriptor
 canonical-oem-somerville-precise-amd64-20130203-1
EcryptfsInUse: Yes
InstallationDate: Installed on 2014-03-03 (56 days ago)
InstallationMedia: Ubuntu 12.04 "Precise" - Build amd64 LIVE Binary 20130203-13:50
SourcePackage: openjdk-6
UpgradeStatus: Upgraded to trusty on 2014-03-04 (55 days ago)

[Sławomir Domagała (slawomir-karol-domagala)]

In openjdk-7-jre the bug doesn't exist.