Strings in android/java, replace() does nothing

Question

In android/java, I'm trying to replace the space in some strings with a +, but it doesn't seem to work. Am I doing it wrong?

String string="Hello world";
string.replace(" ", "+");

I assume it is just for this example, but I just want to point out that I wouldn't name a variable "string".... — Gavin H
– Gavin H, Commented Jan 19, 2011 at 0:29
if you are doing this for url encoding purposes, take a look at the URLEncoder class — kgutteridge
– kgutteridge, Commented Jan 19, 2011 at 0:58

Cristian · Accepted Answer · 2011-01-24 02:42:37Z

26

String objects are immutable, so the replace method doesn't change the string but creates a new one that you have to re-save:

String string="Hello world";
string = string.replace(" ", "+");

answered Jan 19, 2011 at 0:27

Cristian

200k63 gold badges360 silver badges265 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

+1 Exactly. String.replace returns a string. It is an accessor, not a direct mutator.

@jor - if this is the correct answer, check the box next to it so @Cristian gets credit.

rvasa · Accepted Answer · 2011-04-12 23:52:30Z

1

In Java, the StringBuffer class provides a mutable string. The replace method will return the same object.

answered Apr 12, 2011 at 23:52

rvasa

112 bronze badges