Java replaceAll / replace string with instances of dollar sign

Question

public static String template = "$A$B"

public static void somemethod() {
         template.replaceAll(Matcher.quoteReplacement("$")+"A", "A");
         template.replaceAll(Matcher.quoteReplacement("$")+"B", "B");
             //throws java.lang.ArrayIndexOutOfBoundsException: Array index out of range: 3
         template.replaceAll("\\$A", "A");
         template.replaceAll("\\$B", "B");
             //the same behavior

         template.replace("$A", "A");
         template.replace("$B", "B");
             //template is still "$A$B"

}

I don't understand. I used all methods of doing the replacement I could find on the internets, including all stack overflow I could found. I even tried \u0024! What's wrong?

Keppil · Accepted Answer · 2012-09-30T11:42:30.503

6

The replacement isn't done inplace (A String can't be modified in Java, they are immutable), but is saved in a new String that is returned by the method. You need to save the returned String reference for anything to happen, eg:

template = template.replace("$B", "B");

edited Sep 30 '12 at 11:42

answered Sep 30 '12 at 11:36

Keppil

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DAMN! I did it like a milion times before in the correct way. I just forgot it! Thanks! – emha Sep 30 '12 at 11:37
4

@emha If you find the answer useful, why don't you accept it? – RAS Sep 30 '12 at 11:44

score 4 · Answer 2 · answered Sep 30 '12 at 11:39

4

Strings are immutable. So you need to assign the return valur of replaceAll to a new String:

String s = template.replaceAll("\\$A", "A");
System.out.println(s);

answered Sep 30 '12 at 11:39

Suraj Chandran

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Java replaceAll / replace string with instances of dollar sign

2 Answers2