question: private final byte [ ] zeroExtend ( byte [ ] dataToPad ) { assert null != dataToPad ; final int targetLength = 4 ; if ( targetLength <= dataToPad . length ) return dataToPad ; byte padded [ ] = new byte [ targetLength ] ; for ( int i = 0 ; i < dataToPad . length ; i ++ ) padded [ i ] = dataToPad [ i ] ; for ( int i = dataToPad . length ; i < padded . length ; i ++ ) padded [ i ] = ( byte ) 0 ; return padded ; }
target:  If the parameter is shorter than 4 bytes, then create and return a new 4 byte array with the input array's bytes followed by zero bytes. Otherwise return the parameter.