code: public static void fire(Throwable t) {
          if (t != null) {
              // Don't need to do anything special for unchecked exceptions.
              if (t instanceof RuntimeException) {
                  throw (RuntimeException) t;
              }
              if (t instanceof Error) {
                  throw (Error) t;
              }
  
              ThrowUnchecked impl = cImpl;
              if (impl == null) {
                  synchronized (ThrowUnchecked.class) {
                      impl = cImpl;
                      if (impl == null) {
                          cImpl = impl =
                              AccessController.doPrivileged(new PrivilegedAction<ThrowUnchecked>() {
                                  public ThrowUnchecked run() {
                                      return generateImpl();
                                  }
                              });
                      }
                  }
              }
  
              impl.doFire(t);
          }
      }
docs: Throws the given exception, even though it may be checked. This method
  only returns normally if the exception is null.
  
  @param t exception to throw