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Slow Execution and Bad Performance of Java Code at run time

 
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kamran

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Joined: 01 May 2005
Posts: 55

PostPosted: Sun Jun 17, 2012 8:59 pm    Post subject: Slow Execution and Bad Performance of Java Code at run time
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Hi,

While executing ang java code with the java command in omvs I must wait for nearly 30 seconds to get back responses.
executing commands like:

Code:
java -version
java HelloWorld

the same performance issue is distinguishable in WAS v7 which i think it suffers from the JVM environment which is running under.

Unfortunately I am new in customizing JVM under OMVS (zOS).

what can I do to make java code faster in OMVS.

thanks
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Robert Sample

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Joined: 06 Jun 2008
Posts: 8054
Location: East Dubuque, Illinois, USA

PostPosted: Sun Jun 17, 2012 10:13 pm    Post subject:
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Work with your site support group. The slowness could be due to Workload Manager (WLM) policy, or BPXPRMxx having values too small for java, or numerous other possibilities. Without someone at your site looking at what is going on, it is not likely that performance will improve -- and this is certainly NOT an area where an application programmer can make much of a difference.
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kamran

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Joined: 01 May 2005
Posts: 55

PostPosted: Wed Jun 20, 2012 11:17 pm    Post subject: Reply to: Slow Execution and Bad Performance of Java Code at
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Hi,

For those who may have the same problem,After posoting this topic I downloaded Java version 7 from IBM and installed on the machine.
with greate surprise when I run a java class I saw a warnning message about delay in contacting DNS servers. by checking resolv.conf file I saw an invalid DNS ip there. by removing it, running "java HelloWorld just took around a second to finish.The WAS environment also is much more faster now.

I wonder why java interpreter does not handle e.g. nonexistant DNS. or even why it checks DNS on every invocation.
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Bill O'Boyle

CICS Moderator


Joined: 14 Jan 2008
Posts: 2502
Location: Atlanta, Georgia, USA

PostPosted: Wed Jun 20, 2012 11:24 pm    Post subject: Reply to: Slow Execution and Bad Performance of Java Code at
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Interpreted code will run much slower than compiled/object code.

Try compiling the program (IE: like COBOL) and then run it.

I think you'll a find big difference. icon_wink.gif
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