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javaexceptionthrowsthrowable

No exception of type UnderflowException can be thrown;

I am trying to implement a stack with some functions in Java. I have created the class UnderflowException that implements Exception like this:

package exceptions;

public class UnderflowException extends Exception
{
    public UnderflowException(String err)
    {
        super(err);
    }
}

When I'm implementing the Interface I get the following error "No exception of type UnderflowException can be thrown; an exception type must be a class of Throwable" when I try to throw.

My interface looks like this:

import exceptions.*;
public interface Stack
{
    public void push(Object x);
    public void pop() throws UnderflowException;
    public Object top() throws UnderflowException;
    //other functions
}

Is there a problem with the UnderflowException class? Thank you!

Solution

  • Replace Exception with java.lang.Exception. Looks like you use wrong class and FQN help solve problem.