question: public static int compare ( byte [ ] a , byte [ ] b ) { if ( a == b ) return 0 ; if ( a == null ) return - 1 ; if ( b == null ) return 1 ; int len = Math . min ( a . length , b . length ) ; for ( int i = 0 ; i < len ; ++ i ) { int diff = a [ i ] - b [ i ] ; if ( diff != 0 ) return diff ; } if ( a . length > len ) return 1 ; if ( b . length > len ) return - 1 ; return 0 ; }
target:  Compares two byte arrays. Returns <0 if a byte in a is less than the corresponding byte in b, or if a is shorter, or if a is null. Returns >0 if a byte in a is greater than the corresponding byte in b, or if a is longer, or if b is null. Returns 0 if they are equal or both null.