question: public static String byteToHexString ( byte [ ] byteArray ) { StringBuilder builder = new StringBuilder ( ) ; for ( int i = 0 ; i < byteArray . length ; i ++ ) { int byteCode = byteArray [ i ] & 0xFF ; if ( byteCode < 0x10 ) { builder . append ( 0 ) ; } builder . append ( Integer . toHexString ( byteCode ) ) ; } return builder . toString ( ) ; }
target:  byte to hex string