Why Does Integer 200 Behave Differently in Java?🤓

prabash withanachchi

Nov 14, 2025

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Here’s a small but powerful Java concept that many developers overlook and it can even cause unexpected bugs.

A Java byte has 8 bits:

1 sign bit → 0 = positive, 1 = negative

7 value bits → determine the magnitude.

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This gives the range of a byte as:

The smallest value is: 10000000 → -128

The smallest value is: 01111111 → +127

code 1:

Integer a = 200;
Integer b = 200;
System.out.println(a == b); //false

code 2:

Integer a = 100;
Integer b = 100;
System.out.println(a == b); //true

Why This Happens

Java uses an Integer Cache for efficiency:

Numbers between -128 and 127 are cached and reused

Numbers outside this range (like 200) create new objects

So even if a and b hold the same value, == returns false for numbers outside the cache.

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