Why Does Java Output -124 When Converting int to byte?

What is the reason behind Java producing -124 when converting an int value of 132 to a byte?

int i = 132;
byte b = (byte)i; 
System.out.println(b);

When converting an integer value to a byte in Java, if the integer exceeds the range of a byte, Java applies truncation, resulting in unexpected values. This explanation clarifies why converting the int value 132 yields -124 in the byte representation.

int i = 132;
byte b = (byte) i; // This results in -124 due to truncation of higher bits
System.out.println(b); // Output will be -124

Causes

• A byte in Java is an 8-bit signed integer with a range of -128 to 127.
• When the int value 132 is converted to byte, it exceeds the maximum byte range of 127.
• The conversion process truncates the higher bits, resulting in a negative byte value due to the two's complement representation.

Solutions

• To avoid unexpected results, ensure that the integer value falls within the byte range before conversion.
• Use proper casting and validation logic to audit the values being cast to prevent data loss.

Mistake: Assuming all integers can be safely converted to byte without verification.

Solution: Always check the integer value against the byte range before converting.

Mistake: Not understanding how two's complement works, leading to confusion about negative values.

Solution: Familiarize yourself with the concept of two's complement and how it affects binary representations in Java.