how to compare the Java Byte[] array?

Question

public class ByteArr {

    public static void main(String[] args){
        Byte[] a = {(byte)0x03, (byte)0x00, (byte)0x00, (byte)0x00};
        Byte[] b = {(byte)0x03, (byte)0x00, (byte)0x00, (byte)0x00};
        byte[] aa = {(byte)0x03, (byte)0x00, (byte)0x00, (byte)0x00};
        byte[] bb = {(byte)0x03, (byte)0x00, (byte)0x00, (byte)0x00};

        System.out.println(a);
        System.out.println(b);
        System.out.println(a == b);
        System.out.println(a.equals(b));

        System.out.println(aa);
        System.out.println(bb);
        System.out.println(aa == bb);
        System.out.println(aa.equals(bb));
    }
}

I do not know why all of them print false.

When I run "java ByteArray", the answer is "false false false false".

I think the a[] equals b[] but the JVM is telling me I am wrong, why？？

Answer 1

Use Arrays.equals() if you want to compare the actual content of arrays that contain primitive types values (like byte).

System.out.println(Arrays.equals(aa, bb));

Use Arrays.deepEquals for comparison of arrays that contain objects.