8-bit Signed Integer (Java byte)

Java uses 8-bit signed integers for the byte type.
It is represented internally using two’s complement.

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Range of 8-bit Signed byte

A byte has 8 bits:

• 1 bit → sign
• 7 bits → numeric value

This gives the range:

-128 to +127

Because:

Minimum: 1000 0000 (binary) = -128
Maximum: 0111 1111 (binary) = +127

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Binary → Decimal (Signed)

If MSB (most significant bit) = 0

The number is positive.

Example: 0011 0101 → 53

If MSB = 1

The number is negative → use two’s complement:

1. Invert bits
2. Add 1
3. Put minus sign

Example: 1111 0001
Invert → 0000 1110
Add 1 → 0000 1111 = 15
So output = -15

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Decimal → 8-bit Signed Binary

Example: Convert -20

1. Convert +20 → 0001 0100
2. Invert → 1110 1011
3. Add 1 → 1110 1100

Final: 1110 1100

Example: Convert +50

50 → 0011 0010

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Byte Overflow in Java

Java byte overflows automatically (wrap-around).

Example: byte b = 127;
b++;
Output: -128

Because: 0111 1111 (127)

• 1
  = 1000 0000 (-128)

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Common 8-bit Signed Values

Binary	Decimal
1000 0000	-128
1000 0001	-127
1111 1111	-1
0000 0000	0
0000 0001	1
0111 1111	127

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Summary

• byte is an 8-bit signed integer in Java.
• Range: -128 to +127.
• Uses two’s complement.
• MSB = 0 → positive, MSB = 1 → negative.
• Overflow wraps automatically.

This is essential for understanding low-level operations, bit manipulation, and byte-based IO in Java.