add double null check to asm stub builders ------------------------------------------ Key: DROOLS-578 URL: https://issues.jboss.org/browse/DROOLS-578 Project: Drools Issue Type: Patch Security Level: Public(Everyone can see) Affects Versions: 6.1.0.Beta1, 6.1.0.Beta2, 6.1.0.Beta3, 6.1.0.Beta4, 6.1.0.CR1, 6.1.0.CR2, 6.1.0.Final Reporter: david hendi Assignee: Mark Proctor Attachments: asm-builder-double-null-check.patch currently the code generated does a null check within the synchronized code. this forces all threads to block while the check is made even after the check returns false. by adding a double null check, the synchronized code is bypassed once the check is satisfied. public void evaluate(KnowledgeHelper paramKnowledgeHelper, WorkingMemory paramWorkingMemory) throws Exception { if (this.consequence == null) { synchronized (this) { if (this.consequence == null) { ConsequenceGenerator.generate(this, paramKnowledgeHelper, paramWorkingMemory); } } } this.consequence.evaluate(paramKnowledgeHelper, paramWorkingMemory); }