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JavaIntermediate#puzzle#fundamentals

What does this print? Integer a = 127; Integer b = 127; Integer c = 128; Integer d = 128; System.out.println(a == b); System.out.println(c == d);

Integer caches boxed values from -128 to 127 for reuse, so a and b (127) point to the same cached object, making a == b true. 128 is outside the cache range, so c and d are separate objects, making c == d false.

Example
Integer a = 127, b = 127, c = 128, d = 128;
System.out.println(a == b); // true
System.out.println(c == d); // false

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