FULL PRODUCT VERSION :
java version "1.7.0_71"
Java(TM) SE Runtime Environment (build 1.7.0_71-b14)
Java HotSpot(TM) Client VM (build 24.71-b01, mixed mode)

ADDITIONAL OS VERSION INFORMATION :
Microsoft WIndows [ Version 6.4.9879]

EXTRA RELEVANT SYSTEM CONFIGURATION :
Windows 10 Technical Preview (Build 9879), 64-bit

A DESCRIPTION OF THE PROBLEM :
System.getProperty( " os.name " ) returns  " Windows NT (unknown) "  on Windows 10

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Following code should return valid OS name for Windows 10

public class HelloWorld {
     public static void main(String args[]) {
        System.out.println(System.getProperty( " os.name " ));
     }
}

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Valid OS name
ACTUAL -
" Windows NT (unknown) " 

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
public class HelloWorld {
     public static void main(String args[]) {
        System.out.println(System.getProperty( " os.name " ));
     }
}
---------- END SOURCE ----------