自定义异常的使用

package ImoocException;

public class my_Exception extends Exception {

/**

* 

*/

private static final long serialVersionUID = 1L;

public my_Exception() {

System.out.println("使用了这个自定义的类1!");

}

public my_Exception(String str) {

super(str);

System.out.println("使用了这个自定义的类2！");

}

public void devide(int a,int b) throws Exception {

if(b==0) {

throw new my_Exception("被除数不能为0");

}

else {

System.out.println("it is ok!");

}

}

public static void main(String[] args)throws Exception {

// TODO Auto-generated method stub

ImoocException  imooc=new ImoocException ();

try {

imooc.devide(10, 0);

}

catch(my_Exception e) {

   System.out.println("异常抛出！");

}

}

}

最后结果还是出来

Exception in thread "main" java.lang.Exception

at ImoocException.ImoocException.devide(ImoocException.java:6)

at ImoocException.my_Exception.main(my_Exception.java:29)

这是怎么回事？