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1.java static inner class ºÍ non-static inner classµÄÇø±ð?
2.Çëд³öÒ»¸ösingletonģʽµÄclass.
ÄãÈç¹ûд³öÏÂÃæµÄ2ÖÖÑùʽ,ÎÒ»áÎÊÄã:ÇëÎÊÄãÈçºÎÔÚͬһ¸öjvmÖв¢ÇÒÔÚͬһ¸öclassLoaderÖеõ½ËüµÄ¶à¸öʵÀý?(Çë²»ÒªÆæ¹Ö)
ÑùÁÐ1:
public class Singleton {
private final static Singleton instance=new Singleton();
private Singleton(){}
public static Singleton newInstance(){
return instance;
}
}
ÑùÁÐ2:
public class Singleton {
private static volatile int instanceCounter=0;
private Singleton(){
if(instanceCounter>0)
throw new RuntimeException("can't create multi instances!");
instanceCounter++;
}
private final static Singleton instance=new Singleton();
public static Singleton newInstance(){
return instance;
}
}
3.java µÄexception ·Öchecked,unchecked.ÏñRuntimeException,Error¶¼²»ÓÃÏÔʽtry-catch,Ö±½Ó¿ÉÒÔthrow,
µ«ÊÇÒ»°ãµÄexceptionÊDZØÐëcatchµÄ:
throw new Exception("..."),Èç¹ûÕâ¾ä²»ÔÚtry-catchÌåÄÚ,»òÕß·½·¨µÄÉùÃ÷ûÓÐthrows,ÄÇô±àÒëÊÇͨ²»¹ýµÄ.
ok,Çë¿´ÈçϵĴúÂë:
public class TestClass {
public void testMethod()/*ÕâÀïûÓÐthrows Ŷ!*/{
......
throw new Exception("force throw the exception...");
......
}
}
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