Can I change String object's value passed to my method?

Question

I found the following question Is Java "pass-by-reference" or "pass-by-value"?.

I read almost all of it, but could not find out yet what should I do if I want the foo(-) method, to change my String's value? (maybe or not reference too, it doesn't matter to me).

void foo(String errorText){      errorText="bla bla"; }  int main(){      String error="initial";      foo(error);      System.out.println(error); } 

I want to see bla bla on the console. Is it possible?

Answer 1

You can't change the value of errorText in foo as the method is currently declared. Even though you are passing a reference of the String errorText into foo, Java Strings are immutable--you can't change them.

However, you could use a StringBuffer (or StringBuilder). These classes can be edited in your foo method.

public class Test {     public static void foo(StringBuilder errorText){          errorText.delete(0, errorText.length());         errorText.append("bla bla");     }      public static void main(String[] args) {          StringBuilder error=new StringBuilder("initial");         foo(error);          System.out.println(error);     } } 

Other solutions are to use a wrapper class (create a class to hold your String reference, and change the reference in foo), or just return the string.