1. protected static final ThreadLocal<? extends RequestContext> threadLocal = new ThreadLocal<RequestContext>() {
    2.         @Override
    3.         protected RequestContext initialValue() {
    4.             try {
    5.                 return contextClass.newInstance();
    6.             } catch (Throwable e) {
    7.                 throw new RuntimeException(e);
    8.             }
    9.         }
    10.     };