[jira] [Created] (AMQ-4826) Avoid unnecessary remainder operator for floating-point

["Ryuken SEKI (JIRA)" <ji...@apache.org>]

Ryuken SEKI created AMQ-4826:
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             Summary: Avoid unnecessary remainder operator for floating-point
                 Key: AMQ-4826
                 URL: https://issues.apache.org/jira/browse/AMQ-4826
             Project: ActiveMQ
          Issue Type: Improvement
          Components: activemq-camel
    Affects Versions: 5.9.0
         Environment: OS: OpenSUSE 12.2
JDK: Linux ARM Softfloat(jdk-7u45-linux-arm-vfp-sflt.tar.gz)
Hardware: pandaboard
            Reporter: Ryuken SEKI
            Priority: Minor


I installed jdk-7u45-linux-arm-vfp-sflt.tar.gz on my pandaboard, and found that this jdk has a problem of remainder operator for floating point. So, if you starts ActiveMQ in above environment, you might encounter IndexOutOfBoundsException at
  org.apache.activemq.transport.failover.FailoverTransport.getConnectList(FailoverTransport.java:779)

This is because
  int p = (int) (Math.random() * 100 % l.size());
above p gets larger number than "l.size" contrary to your expectation. This problem doesn't occur in case of x86 Architecture or ARM Hardfloat JDK.

This is a problem of ARM Softfloat JDK, but I think it's better to avoid unnecessary remainder operator for floating-point for safety. So, 
  int p = ((int) Math.random() * 100) % l.size();
would be better than current one.



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