Hello,

I have a project, that uses Drools 5.0.1. I have a class, called RuleFlowProcessor, that’s used to apply some of my rules to the objects.

The instances of RuleFlowProcessor with the identical configuration should be used by different threads, and i use following mechanism:

I initialize one instance of RuleFlowProcessor, and the threads take copy of this instance, calling the ‘clone()’ method, which is not synchronized, and in which I just create new instance of

RuleFlowProcessor and init it, using the same data.

And therefore I get an exception:

Exception in thread "Thread-91" [Error: incomplete statement:  (possible use of reserved keyword as identifier: )]

[Near : {... globals != empt ....}]

                      ^

[Line: 0, Column: 0]

            at org.mvel2.MVELInterpretedRuntime.parseAndExecuteInterpreted(MVELInterpretedRuntime.java:153)

            at org.mvel2.MVELInterpretedRuntime.parse(MVELInterpretedRuntime.java:44)

            at org.mvel2.MVEL.eval(MVEL.java:514)

although, all the resources (.drl and .rf files) are parsed perfectly, when I use just one thread.

In actions of my ruleflow, the dialect: ‘mvel’ was set by default, if I set dialect to ‘java’ without modifying any code, the error doesn’t occur.

The full stacktrace is in attach. I can send the project, that reproduces the problem, if needed.

Best regards,

Grigoriy Grigoriev.