I'm trying to fix an issue, in my application I have this code
try {
object1.method1();
} catch(Exception ex) {
JOptionPane.showMessageDialog(nulll, "Error: "+ex.getMessage());
}
and the object1 would do something like that:
public void method1() {
//some code...
throw new RuntimeException("Cannot move file");
}
I get a messsage in my option pane like this:
Error: java.lang.RuntimeException: Cannot move file
but I used getMessage and not toString method, so the name of the class shouldn´t appear, right?
What I am doing wrong?
I already tryied with a lot of exceptions, even Exception itself. I'm looking to solve this no without the need to implement my own Exception subclass
PROBLEM SOLVED - thank you all!
The try and catch were actually being called in get() method from SwingWorker which constructs an ExecutionException with my exception thrown from doInBackground()
I fixed doing this:
@Override
protected void done() {
try {
Object u = (Object) get();
//do whatever u want
} catch(ExecutionException ex) {
JOptionPane.showMessageDialog(null, "Error: "+ex.getCause().getMessage());
} catch(Exception ex) {
JOptionPane.showMessageDialog(null, "Error: "+ex.getMessage());
}
}
This question is related to
java
exception-handling
I think you are wrapping your exception in another exception (which isn't in your code above). If you try out this code:
public static void main(String[] args) {
try {
throw new RuntimeException("Cannot move file");
} catch (Exception ex) {
JOptionPane.showMessageDialog(null, "Error: " + ex.getMessage());
}
}
...you will see a popup that says exactly what you want.
However, to solve your problem (the wrapped exception) you need get to the "root" exception with the "correct" message. To do this you need to create a own recursive method getRootCause:
public static void main(String[] args) {
try {
throw new Exception(new RuntimeException("Cannot move file"));
} catch (Exception ex) {
JOptionPane.showMessageDialog(null,
"Error: " + getRootCause(ex).getMessage());
}
}
public static Throwable getRootCause(Throwable throwable) {
if (throwable.getCause() != null)
return getRootCause(throwable.getCause());
return throwable;
}
Note: Unwrapping exceptions like this however, sort of breaks the abstractions. I encourage you to find out why the exception is wrapped and ask yourself if it makes sense.
My guess is that you've got something in method1 which wraps one exception in another, and uses the toString() of the nested exception as the message of the wrapper. I suggest you take a copy of your project, and remove as much as you can while keeping the problem, until you've got a short but complete program which demonstrates it - at which point either it'll be clear what's going on, or we'll be in a better position to help fix it.
Here's a short but complete program which demonstrates RuntimeException.getMessage() behaving correctly:
public class Test {
public static void main(String[] args) {
try {
failingMethod();
} catch (Exception e) {
System.out.println("Error: " + e.getMessage());
}
}
private static void failingMethod() {
throw new RuntimeException("Just the message");
}
}
Output:
Error: Just the message
Source: Stackoverflow.com