Throwing exception in overriding methods

[Veena Pointi]

public class TechnoSample4  {
  
  public static void main(String[] args) {
 
    TechnoSampleSub myref = new TechnoSampleSub();
 
    try{//line1
 
      myref.test();
 
    } catch(Exception e) {}
  
  }
  
  void test() throws Exception{
    
    System.out.println("In TechnoSample");
    throw new Exception();
  }
}
 
class TechnoSampleSub extends TechnoSample4 {
 
  void test() {
    
    System.out.println("In TechnoSampleSub");
  }
}

The above code compiles & runs successfully.Shouldn't it give compiler error due to try catch block in line1?Coz Exception that is never thrown is caught?
Veena
[ edited to format code for easier reading -ds ]
[ September 15, 2003: Message edited by: Dirk Schreckmann ]

[Anupreet Arora]

Hi,

Shouldn't it give compiler error due to try catch block in line1?Coz Exception that is never thrown is caught?

The variable myref is a reference of type TechnoSampleSub. The method test is called on an object of TechnoSampleSub type.
This throws no exception and hence no problems. Even if an excpeion were to arise, it would be caught by the catch block specified.
Regards,
Anupreet

[Cody Beth]

Hi Veena,
Compiler will not display any error even though java.lang.Exception is not thrown by the test() method because of the following reason:
1) java.lang.Exception class is a parent class of unchecked (RuntimeException, ) and checked exceptions. So there are chances that the code written in the try block throws any of the unchecked exceptions.So the compiler will never throw an error.
Note: Even if there is no code in try block and Exception object is caught in the catch block , the compiler will never complain.
But if we catch IOException(checked Exception) , then the compiler gives the error that
"exception java.io.IOException is never thrown in body of corresponding try statement".
This is because IOException is not thrown by any of statements in the try block.

I hope this clarifies your doubt.
Regards,
Cody

[Veena Pointi]

Thanks Cody.It is clear now.