How to return a value from try, catch, and finally?

Question

So when I do a code of blocks inside a try{}, and I try to return a value, it tells me

no return values

import org.w3c.dom.ranges.RangeException;   public class Pg257E5  { public static void main(String[]args) {     try     {         System.out.println(add(args));     }     catch(RangeException e)     {         e.printStackTrace();     }     finally     {         System.out.println("Thanks for using the program kiddo!");     } } public static double add(String[] values) // shows a commpile error here that I don't have a return value {     try     {         int length = values.length;         double arrayValues[] = new double[length];         double sum = 0;         for(int i = 0; i<length; i++)         {             arrayValues[i] = Double.parseDouble(values[i]);             sum += arrayValues[i];         }         return sum; // I do have a return value here.         // Is it because if the an exception occurs the codes in try stops and doesn't get to the return value?     }     catch(NumberFormatException e)     {         e.printStackTrace();     }     catch(RangeException e)     {         throw e;     }     finally     {         System.out.println("Thank you for using the program!");         //so would I need to put a return value of type double here?     }  } } 

My question is, how do you return a value when you are using try and catch?

Answer 1

To return a value when using try/catch you can use a temporary variable, e.g.

public static double add(String[] values) {     double sum = 0.0;     try {         int length = values.length;         double arrayValues[] = new double[length];         for(int i = 0; i < length; i++) {             arrayValues[i] = Double.parseDouble(values[i]);             sum += arrayValues[i];         }     } catch(NumberFormatException e) {         e.printStackTrace();     } catch(RangeException e) {         throw e;     } finally {         System.out.println("Thank you for using the program!");     }     return sum; } 

Else you need to have a return in every execution path (try block or catch block) that has no throw.

Answer 2

It is because you are in a try statement. Since there could be an error, sum might not get initialized, so put your return statement in the finally block, that way it will for sure be returned.

Make sure that you initialize sum outside the try/catch/finally so that it is in scope.