convert a byte array to string

You could convert the byte array to a char array, and then construct a string from that

scala> val bytes = Array[Byte]('a','b','c','d')
bytes: Array[Byte] = Array(97, 98, 99, 100)

scala> (bytes.map(_.toChar)).mkString 
res10: String = abcd

scala> 

You can always convert the byte array to a string if you know its charset,

val str = new String(bytes, StandardCharsets.UTF_8)

And the default Charset would used if you don't specify any.