检测运行内存

public static void test(){
	      for (int j = 0; j < 100000; j++) {  
	    	         Object o = new Object();  
	    	         }  
	    	  
	    	        System.out.println("总内存：" + Runtime.getRuntime().totalMemory()  
	    	                 / 1024 / 1024 + "M");  
	    	          System.out.println("空闲内存：" + Runtime.getRuntime().freeMemory()  
	    	                  / 1024 / 1024 + "M");  
	    	          System.out.println("已使用内存："  
	    	                  + (Runtime.getRuntime().totalMemory() - Runtime  
	    	                          .getRuntime().freeMemory()) / 1024 / 1024 + "M");

	}