json - Can't parse Date with DateTimeFormat -

i can't string parsed datetimeformat format. here input string : thu apr 07 00:00:00 edt 2011

and format:
datetimeformat.getformat("eee mmm dd hh:mm:ss vvv yyyy");

i've read correct format string, me it's not parsing correctly. here code:

public class ycdatecolumn extends textcolumn<jsonobject> {      datetimeformat fmtc = datetimeformat.getformat("dd-mmm-yyyy");     datetimeformat fmtb = datetimeformat.getformat("mmm dd, yyyy hh:mm:ss a");     datetimeformat fmta = datetimeformat.getformat("eee mmm dd hh:mm:ss vvv yyyy");       private string key = null;     private string def = null;      public ycdatecolumn(string akey, string adefault) {         super();         key = akey;         def = adefault;     }      public ycdatecolumn(string akey) {         this(akey, null);     }      @override     public string getvalue(jsonobject aobj) {             system.out.println("ycdatecolumn - object= " + aobj);         jsonvalue mval = aobj.get(key);         if (mval == null)             return def;         system.out.println("ycdatecolumn -  parse string: " + mval.isstring().stringvalue());         return fmtc.format(fmta.parse(mval.isstring().stringvalue()));     }  } 

the last system.out prints text (the string parse): ycdatecolumn - parse string: thu apr 07 00:00:00 edt 2011

what missing!? help!

-eric

zzz in format string requires number (the offset). date has edt. need use v timezone.