code: protected static void setupScriptEngine() {
          new Thread(() -> {
              /* first getEngineByName() costs about 0.5 seconds so initialize it background */
              final Class<?> engineType = LastaDiProperties.getInstance().getDiXmlScriptExpressionEngineType();
              if (engineType == null) { /* use default */
                  new ScriptEngineManager().getEngineByName("javascript"); /* initialize static resources */
              }
          }).start();
      }
docs: -------------