这里面包含了一百多个JAVA源文件

				Class cls = java.lang.String.class;
				    Class sup = cls.getSuperclass();  // java.lang.Object
				    
				    cls = java.lang.Object.class;
				    sup = cls.getSuperclass();        // null
				    
				    // The superclass of interfaces is always null
				    cls = java.lang.Cloneable.class;
				    sup = cls.getSuperclass();        // null
				    
				    // The superclass of primitive types is always null
				    cls = int.class;
				    sup = cls.getSuperclass();        // null