question: public static DateTimeZone readFrom ( DataInput in , String id ) throws IOException { switch ( in . readUnsignedByte ( ) ) { case 'F' : DateTimeZone fixed = new FixedDateTimeZone ( id , in . readUTF ( ) , ( int ) readMillis ( in ) , ( int ) readMillis ( in ) ) ; if ( fixed . equals ( DateTimeZone . UTC ) ) { fixed = DateTimeZone . UTC ; } return fixed ; case 'C' : return CachedDateTimeZone . forZone ( PrecalculatedZone . readFrom ( in , id ) ) ; case 'P' : return PrecalculatedZone . readFrom ( in , id ) ; default : throw new IOException ( "Invalid encoding" ) ; } }
target:  Decodes a built DateTimeZone from the given stream, as encoded by writeTo.