Hello. Here is my code:

import java.util.Scanner;

public class SpaceBoxer{
  public static double planets(int world){
    double planetmulti;

    if (world == 1){
      planetmulti = 0.78;
    }
    else if (world == 2){
      planetmulti = 0.39;
    }
    else if (world == 3){
      planetmulti = 2.65;
    }
    else if (world == 4){
      planetmulti = 1.17;
    }
    else if (world == 5){
      planetmulti = 1.05;
    }
    else if (world == 6){
      planetmulti = 1.23;
    }
    return planetmulti;
  }
  public static void main(String[] args){
    Scanner keyboard = new Scanner(System.in);

    int weight, theplanet;
    System.out.print("What is your weight?");
    weight = keyboard.nextInt();

    System.out.println("Okay, now what planet are you visiting?");
    System.out.println("   1. Venus   2. Mars    3. Jupiter");
    System.out.println("   4. Saturn  5. Uranus  6. Neptune");
    theplanet = keyboard.nextInt();

    System.out.println("Okay, so your weight would on "   weight * planets(theplanet));
  }
}

When I try to compile, however, I get this error:

SpaceBoxer.java:25: error: variable planetmulti might not have been initialized. 

return planetmulti;
       ^

Any help? Is it due to me declaring it a double instead of something else? I'm not sure what I'm doing wrong here.