Runtime exception

[Arjun Shastry]

Hi,
I am working on Exception related problem occuring in application. The application java program listens on a port waiting for third party XML message. After receiving the message, program checks for "<" tag and then performs necessary transformation. Program is using String.indexOf() method to do this.If third party does not send message containging "<" then ArrayIndexOutofBoundsException is thrown and thread is killed.
My question is how does program recovers from Runtime Exception?

Thanks

[Christophe Verré]

how does program recovers from Runtime Exception

It doesn't, unless you explicitly catch the exception. But if the exception is thrown by your application, isn't there a way to avoid it to happen ? What is the cause of the exception ?

[Jaydeep Mazumdar]

A RuntimeException indicates something bad with your programming logic/code. This type of exception can be completely avoided by fixing the code/changing the code logic.

In your particular case, String.indexOf() method returns index of "<" in your message or -1 when it does not find it. I believe you are trying to access the array with this index returned. All you need to do is before accessing the array check that the index value returned is >= 0.

That's all!

[Arjun Shastry]

Thanks for quick response.
The exception thrown is "java.lang.StringIndexOutOfBoundsException: String index out of range: -1" Are you saying similar following code is required?

if(input.indexOf("<") != -1 ){
//Then only process the input.
}
else{
//do nothing
}
    

[Jaydeep Mazumdar]

Correct! That would work!

I was suggesting this:

if(input.indexOf("<") >= 0 ){   
//Then only process the input.   
}   
else{   
//do nothing   
}  

[Christophe Verré]

//do nothing  

Or log the error, or throw a checked exception that you would handle somewhere else. It depends on what you want to do with this unexpected message.

[David Newton]

Or use a real web service library with a real parser.