[GROOVY-5241] GroovyScriptEngineImpl could use ConcurrentHashMaps

• Type: Improvement
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 1.8.5, 2.0-beta-2
• Fix Version/s: 1.8.6, 2.0-beta-3
• Labels: concurrency performance
• Assignee: Cédric Champeau
• Reporter: Matt Passell
• Created: 06/Jan/12 16:31
• Updated: 12/Feb/12 04:03
• Resolved: 06/Feb/12 02:43

Description

The Groovy implementation of JSR-223 (Scripting for the Java Platform), GroovyScriptEngineImpl, uses Collections.synchronizedMap(new HashMap()) for the caches of compiled scripts and closures. Since JSR-223 was first supported in Java 6, it's safe to instead use ConcurrentHashMap for those data structures. According to JCIP (Java Concurrency in Practice), ConcurrentHashMap performs substantially better than Hashtable or Collections.synchronizedMap(). In addition, once ConcurrentHashMaps are used, the code could take advantage of additional methods provided in the ConcurrentMap interface, such as putIfAbsent().