FULL PRODUCT VERSION :
java version "1.6.0_24"
Java(TM) SE Runtime Environment (build 1.6.0_24-b07)
Java HotSpot(TM) Client VM (build 19.1-b02, mixed mode, sharing)

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows XP [Version 5.1.2600]

A DESCRIPTION OF THE PROBLEM :
  public void test(){
    String s1 = "\u20ac";
// or
// String s1 = "€";
    s1 = s1.replaceAll("\u20ac", "$");
// or
// s1 = s1.replaceAll("€", "$");
    System.out.println(s1);
  }

causes
Exception in thread "main" java.lang.StringIndexOutOfBoundsException: String index out of range: 1

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
run:

  public void test(){
    String s1 = "\u20ac";
// or
// String s1 = "€";
    s1 = s1.replaceAll("\u20ac", "$");
// or
// s1 = s1.replaceAll("€", "$");
    System.out.println(s1);
  }

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
output of $ not an exception
ACTUAL -
Exception in thread "main" java.lang.StringIndexOutOfBoundsException: String index out of range: 1
at java.lang.String.charAt(Unknown Source)
at java.util.regex.Matcher.appendReplacement(Unknown Source)
at java.util.regex.Matcher.replaceAll(Unknown Source)
at java.lang.String.replaceAll(Unknown Source)
...

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------

  public void test(){
    String s1 = "\u20ac";
// or
// String s1 = "€";
    s1 = s1.replaceAll("\u20ac", "$");
// or
// s1 = s1.replaceAll("€", "$");
    System.out.println(s1);
  }
---------- END SOURCE ----------