Last friday, I had the next situation. In drools 4.0.7 I had the expression: new double[]{-1, 1}
And it worked.

But in Drools 5.0 I had to erase the blank space (before "1" and after ","), because I was getting a warning message, during knowledge base building :

"line 29:114 extraneous input '1' expecting RIGHT_CURLY"

and an exception, during rule execution :

"org.drools.runtime.rule.ConsequenceException: java.lang.IndexOutOfBoundsException"

So the working expression for Drool 5.0 was: new double[]{-1,1}

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Luis Enrique Silva Valdivieso