ADDITIONAL SYSTEM INFORMATION :
$ java -version
java version "1.8.0_131"
Java(TM) SE Runtime Environment (build 1.8.0_131-b11)
Java HotSpot(TM) 64-Bit Server VM (build 25.131-b11, mixed mode)

A DESCRIPTION OF THE PROBLEM :
The replaceAll behavior treats '^' and '$' inconsistently.

'$' counts two:

import java.util.regex.Pattern;
class Test {
    public static void main(String[] args) {
        String input = "a\nb\nc\n";
        Pattern pattern = Pattern.compile("$");
        String result = pattern.matcher(input).replaceAll("XXX");
        System.out.println("a\nb\ncXXX\nXXX".equals(result)); // true
    }
}

and '^' counts one:

import java.util.regex.Pattern;
class Test {
    public static void main(String[] args) {
        String input = "a\nb\nc\n";
        Pattern pattern = Pattern.compile("^");
        String result = pattern.matcher(input).replaceAll("XXX");
        System.out.println("XXXa\nb\nc\n".equals(result)); // true
    }
}

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
See description.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
The start of line and end of line matcher should return the same number of results.

In this case, I think '$' should return "a\nb\nc\nXXX".
ACTUAL -
See description.

---------- BEGIN SOURCE ----------
See description.
---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
None.

FREQUENCY : always