ADDITIONAL SYSTEM INFORMATION :
Windows/JRE 8

A DESCRIPTION OF THE PROBLEM :
When the timezone is set to Eastern Standard Time_dstoff then TimeZone.getID would return the Id in "GMT-05:00" format and not "Continent/City" format as there are no entries for Eastern Standard Time_dstoff in tzmappings

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Set System time zone to Easter Standard Time_dstoff
Get the the default time zone in java
Get The zone id for the timezone

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Id returned is in format "Continent/City"
ACTUAL -
Id Returned is in format "GMT-00:00"

---------- BEGIN SOURCE ----------
import java.util.TimeZone;

public class Main {

    public static void main(String[] args)
    { TimeZone timezone = TimeZone.getTimeZone("America/Cayman");
        System.out.println(timezone.getID());
    }
}
---------- END SOURCE ----------

FREQUENCY : always