stack-allocation

This question already has an answer here: Eligibility for escape analysis / stack allocation with Java 7 3 answers Since somewhere around Java 6, the Hotspot JVM can do escape analysis and allocate non-escaping objects on the stack instead of on the garbage collected heap. This results in a speedup of the generated code and reduces pressure on the garbage collector. What are the rules for when Hotspot is able to stack allocate objects? In other words when can I rely on it to do stack allocation? edit : This question is a duplicate, but (IMO) the answer below is a better answer than what is