To convert a binary byte to octal just divide the byte into three nibbles. The first nibble has two bits and the next two nibbles each have three. For example, convert the binary value 01010011 to octal.

Binary 01 010 011
Octal   1   2   3

To convert a binary value to hexadecimal just divide the byte into two nibbles of four bits each.

Binary 0111 1111
Hex       7    f

The following table demonstrates a set of conversions.

Base Conversion Table

Decimal	Binary	Octal	Binary	Hexadecimal
0	00 000 000	0	0000 0000	0
1	00 000 001	1	0000 0001	1
2	00 000 010	2	0000 0010	2
3	00 000 011	3	0000 0011	3
4	00 000 100	4	0000 0100	4
5	00 000 101	5	0000 0101	5
6	00 000 110	6	0000 0110	6
7	00 000 111	7	0000 0111	7
8	00 001 000	10	0000 1000	8
9	00 001 001	11	0000 1001	9
10	00 001 010	12	0000 1010	a
11	00 001 011	13	0000 1011	b
12	00 001 100	14	0000 1100	c
13	00 001 101	15	0000 1101	d
14	00 001 110	16	0000 1110	e
15	00 001 111	17	0000 1111	f
16	00 010 000	20	0001 0000	10
26	00 011 010	32	0001 1010	1a
36	00 100 100	44	0010 0100	24
46	00 101 110	56	0010 1110	2e
56	00 111 000	70	0011 1000	38
66	01 000 010	102	0100 0010	42
76	01 001 100	114	0100 1100	4c
86	01 010 110	126	0101 0110	56
96	01 100 000	140	0110 0000	60
106	01 101 010	152	0110 1010	6a
116	01 110 100	164	0111 0100	74
126	01 111 110	176	0111 1110	7e

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Here's an example question that prints Byte.MAX_VALUE in binary, octal, decimal, and hex.

Question 9

class A {
  public static void main(String args[]) {
    System.out.print(Integer.toBinaryString(Byte.MAX_VALUE)+",");
    System.out.print(Integer.toOctalString(Byte.MAX_VALUE)+",");
    System.out.print(Integer.toString(Byte.MAX_VALUE)+",");
    System.out.print(Integer.toHexString(Byte.MAX_VALUE));
  }
}


What is the result of attempting to compile and run the program?

a.  Prints: 1111111,177,127,7f
b.  Prints: 11111111,377,256,ff
c.  Compiler Error
d.  Runtime Error
e.  None of the Above

The binary representation of Byte.MAX_VALUE is as follows.

01111111

The Integer.toBinaryString method does not print the leading zero. Instead, it only prints the seven bits that are set to one as follows.

1111111

To convert the binary byte to octal just divide the byte into three nibbles.

Binary 01 111 111
Octal   1   7   7

To convert Byte.MAX_VALUE to hexadecimal just divide the byte into two four bit nibbles.

Binary 0111 1111
Hex       7    f

To convert Byte.MAX_VALUE to decimal raise 2 to the seventh power and then subtract one. The result is 127.