这里面包含了一百多个JAVA源文件

				There are three ways to retrieve a Class object. 
				    // By way of an object
				    Class cls = object.getClass();
				    
				    // By way of a string
				    try {
				        cls = Class.forName("java.lang.String");
				    } catch (ClassNotFoundException e) {
				    }
				    
				    // By way of .class
				    cls = java.lang.String.class;