A memo to use byte in java code.

testByte.java

public class testByte {

  public static void main(String[] args) {
    byte byteData = (byte) 0xC7;  // 11000111
                                  // If there is no "(byte)", 0xC7 is looked as int.
    System.out.println(byteData); // -57

    int intData =  0xC7;         // 00000000 00000000 00000000 11000111
    System.out.println(intData); // 199


    int castedData = (int)byteData; // 11111111 11111111 11111111 11000111
    System.out.println(castedData); // -57


    int positiveNumber = byteData & 0xff; // 11111111 11111111 11111111 11000111 & 00000000 00000000 00000000 11111111
                                          // 0xff is looked as int, so this is "int" & "int".
                                          // Result: 00000000 00000000 00000000 11000111
    System.out.println(positiveNumber);   // 199
  }
}