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Running a new drools project in Eclipse 3.2

Posted on 2006-07-19
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Last Modified: 2012-08-14
hi!  

Has anybody worked on eclipse IDE on drools rule engine?  I add the plugin in 3.2 and created a new drools project.  It comes with a drl file  "Rule.java.drl"  and a test file (with a main class in it) "DroolsTest.java".  The project should run as it is acorrding to docs but is giving an error

"could not find main class, program will exit"

Somehow cannot find the main class?  Any clue why? I think I have all the classpath set.

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Question by:subirc
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Author Comment

by:subirc
ID: 17137558
Any help appreciated --- thanks!!! I must be missing something in eclipse configuration

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Expert Comment

by:mayankeagle
ID: 17137981
How exactly are you running? Did you right-click on DroolsTest.java and select Run As -> Java Application, or select from the Run menu -> Run As -> Java Application.
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Author Comment

by:subirc
ID: 17143680
Tried both -  didn't work either way
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Author Comment

by:subirc
ID: 17143860
This is the error I am getting.....

java.lang.UnsupportedClassVersionError: org/drools/RuleBase (Unsupported major.minor version 49.0)
      at java.lang.ClassLoader.defineClass0(Native Method)
      at java.lang.ClassLoader.defineClass(Unknown Source)
      at java.security.SecureClassLoader.defineClass(Unknown Source)
      at java.net.URLClassLoader.defineClass(Unknown Source)
      at java.net.URLClassLoader.access$100(Unknown Source)
      at java.net.URLClassLoader$1.run(Unknown Source)
      at java.security.AccessController.doPrivileged(Native Method)
      at java.net.URLClassLoader.findClass(Unknown Source)
      at java.lang.ClassLoader.loadClass(Unknown Source)
      at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
      at java.lang.ClassLoader.loadClass(Unknown Source)
      at java.lang.ClassLoader.loadClassInternal(Unknown Source)
Exception in thread "main"
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LVL 30

Accepted Solution

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mayankeagle earned 40 total points
ID: 17143865
Oh then its a version error. That class was developed for a different version of Java and your default version in the Eclipse project is something else. Try changing the JRE in Eclipse (for this project) to point to another version.
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Author Comment

by:subirc
ID: 17143984
do you mean jdk1.5?  I have 1.4.2 and I also tried with the IMB_jre that comes when you install Websphere........
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Expert Comment

by:mayankeagle
ID: 17144032
Well I'm not sure which version drools needs. Maybe it needs Java 5 - you can try installing the runtime for that from Sun's site http://java.sun.com/j2se/ and configure it with Eclipse (you can have multiple JREs installed on a machine but the one that matters for Eclipse is the one the project is configured with).
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Expert Comment

by:mayankeagle
ID: 17144345
Which version did you try?
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Author Comment

by:subirc
ID: 17145596
jre 1.5.0_04  from sun  
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Expert Comment

by:mayankeagle
ID: 17145727
Any reason for the B grade?
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