Bug 58477 - __javaScript function : Allow use of Nashorn engine for J…

…ava8 and upper versions

Take into account sebb feedback
Bugzilla Id: 58477

git-svn-id: https://svn.apache.org/repos/asf/jmeter/trunk@1709166 13f79535-47bb-0310-9956-ffa450edef68

src/functions/org/apache/jmeter/functions/JavaScript.java

@@ -58,13 +58,13 @@ private static class LazyHolder {
     }
 
     private static final boolean USE_RHINO_ENGINE = 
-            getInstance().getEngineByName(JavaScript.NASHORN_ENGINE_NAME) == null ||
-            JMeterUtils.getPropDefault(USE_RHINO_ENGINE_PROPERTY, true) ;
+            JMeterUtils.getPropDefault(USE_RHINO_ENGINE_PROPERTY, true) || 
+            (getInstance().getEngineByName(JavaScript.NASHORN_ENGINE_NAME) == null);
 
     /**
      * @return ScriptEngineManager singleton
      */
-    public static ScriptEngineManager getInstance() {
+    private static ScriptEngineManager getInstance() {
             return LazyHolder.INSTANCE;
     }
     private static final List<String> desc = new LinkedList<>();