Sending a variable to another class for the variable to change Java

Question

Ok i need the string "H" to change to "KeyEvent.VK_+ (the string H thats entered)" And for some reason I can not get the variable to change from H to the new string in the main class. It does change in the other class though. Any help would be great.

Main Class

Convert ConvertObject = new Convert();
String word = "H"
ConvertObject.Convert(word);
System.out.println(word); // this keeps printing out H but it needs to print out  
                                                                 "KeyEvent.VK_H"

Convert Class

public static String Convert(String x) {
    x = "KeyEvent.VK_" + x;
    System.out.println(x);
    return x;

This answer might help you: http://stackoverflow.com/a/9404727/597657 — Eng.Fouad, May 11 '13 at 22:40

score 7 · Accepted Answer · answered May 11 '13 at 22:27

7

Since Java uses pass by value, any modification in the method is done to the local variable only. You need to save the result of the method to get the desired effect:

word = ConvertObject.Convert(word);

answered May 11 '13 at 22:27

Keppil

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+1 If `String` is mutable and has method such as `setVlaue(newString)`, then that would work ;) – Eng.Fouad May 11 '13 at 22:38

score 0 · Answer 2 · answered May 11 '13 at 22:30

0

Everything in Java is pass by value which means that a copy of the String is passed to your method and this is changed, not the original object in the Main class.

answered May 11 '13 at 22:30

JamesB

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To be precise: Not a copy of the String is passed to the method, but a copy of the reference to that String is passed to the method. That way you can change mutable objects in methods and the changes will persist after the method terminates. Strings are immutable, though. – jlordo May 11 '13 at 23:06

Sending a variable to another class for the variable to change Java

2 Answers2