Here you can find the source of resolveSingle(Object object)
public static Object resolveSingle(Object object)
//package com.java2s; //License from project: LGPL import java.util.concurrent.Callable; public class Main { public static Object resolveSingle(Object object) { try {//from ww w . ja va 2 s . c o m return object instanceof Callable ? ((Callable<?>) object).call() : object; } catch (Exception e) { throw new RuntimeException(e); } } }