question: public static byte [ ] concat ( final byte [ ] ... arrays ) { int totalSize = 0 ; for ( final byte [ ] array : arrays ) { totalSize += array . length ; } int startIndex = 0 ; final byte [ ] result = new byte [ totalSize ] ; for ( final byte [ ] array : arrays ) { System . arraycopy ( array , 0 , result , startIndex , array . length ) ; startIndex += array . length ; } return result ; }
target:  Concatenates byte arrays and returns the result.