FULL PRODUCT VERSION :
java version "1.7.0_67"
Java(TM) SE Runtime Environment (build 1.7.0_67-b01)
Java HotSpot(TM) 64-Bit Server VM (build 24.65-b04, mixed mode)

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows [Version 6.1.7601]

A DESCRIPTION OF THE PROBLEM :
Incorrect evaluation of named groups when matching regular expression.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Run SSCCE.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
true
null
2

ACTUAL -
true
2.
2


REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
package main;

import static java.util.regex.Pattern.compile;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Main {

    public static void main(String... args) {
        Pattern pattern = compile("(?i)^(?>(?>(?<mesic>\\d{1,2}+)\\.)?+(?<znamenkoRoku>[+-])?+(?<rok>\\d{1,4}+)|(?>(?<polovinaIndex>[12]\\.?+)?+(?<polovina>polovina|pol\\.?+)|(?<tretina>[1-3])\\.?+(?>tretina|tret\\.?+|tr\\.?+)|(?<ctvrtina>[1-4])\\.?+(?>ctvrtina|ctvrt\\.?+|ct\\.?+)|(?<leta>[1-9]0)\\.?+leta)?(?>(?<znamenkoLeti>[+-])?+(?<leti>\\d{1,2}+)\\.?+(?>(?<stoleti>stoleti|stol\\.?+|st\\.?+)|(?>tisicileti|tis\\.?+|t\\.?+))))(?<letopocet>(?<nl>n\\.?+l\\.?+)|(?>(?>pred|pr|p)\\.?+n\\.?+l\\.?+))?+$");
        Matcher matcher = pattern.matcher("2.tisiciletipredn.l.");
        System.out.println(matcher.matches());
        System.out.println(matcher.group("polovinaIndex"));
        System.out.println(matcher.group("leti"));
    }

}

---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
Use this regular expression instead (unescaped): (?i)^(?>(?>(?<mesic>\d{1,2}+)\.)?+(?<znamenkoRoku>[+-])?+(?<rok>\d{1,4}+)|(?>(?<polovinaIndex>[12]\.?+)?(?<polovina>polovina|pol\.?+)|(?<tretina>[1-3])\.?+(?>tretina|tret\.?+|tr\.?+)|(?<ctvrtina>[1-4])\.?+(?>ctvrtina|ctvrt\.?+|ct\.?+)|(?<leta>[1-9]0)\.?+leta)?(?>(?<znamenkoLeti>[+-])?+(?<leti>\d{1,2}+)\.?+(?>(?<stoleti>stoleti|stol\.?+|st\.?+)|(?>tisicileti|tis\.?+|t\.?+))))(?<letopocet>(?<nl>n\.?+l\.?+)|(?>(?>pred|pr|p)\.?+n\.?+l\.?+))?+$

SUPPORT :
YES