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: stackoverflow.com/a/9404727/597657 — Eng.Fouad
– Eng.Fouad, Commented May 11, 2013 at 22:40

Keppil · Accepted Answer · 2013-05-11 22:27:10Z

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, 2013 at 22:27

Keppil

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1 Comment

Eng.Fouad Over a year ago

+1 If String is mutable and has method such as setVlaue(newString), then that would work ;)

JamesB · Accepted Answer · 2013-05-11 22:30:17Z

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, 2013 at 22:30

JamesB

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1 Comment

jlordo Over a year ago

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.

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