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关于Constructor call must be the first statement in a constructor的问题

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今天面试碰到一道题,是关于Constructor call must be the first statement in a constructor的问题的。

题目是这样的
public class TestA {
     public TestA(){
    	 System.out.println("A");
     }
}
public class TestB extends TestA {
	
   protected TestB(Object a){
	   System.out.println("B");
   }
   public TestB(){
	   super();
	   this.TestB(new Object());   
   }
}
public class Test {
 public static void main(String[] ars)
 {
	 new TestB();
 }
}

super()和this.TestB(new Object());不能共存,否则编译时会报异常,换句话说就是super()和this.TestB(new Object());都必须在方法(构造方法)的第一行。

因此要成功编译上面的代码,必须要把TestB(Object a)这个方法修改成非构造方法,比如在前面加上void。

要了解更多请参考http://java.syntaxerrors.info/index.php?title=Constructor_call_must_be_the_first_statement_in_a_constructor
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