Solution:Step 1: Recall Integer cache rangeJava caches Integer objects for values from -128 to 127, so a and b reference the same object.Step 2: Analyze comparison resultsc and d are outside cache range, so they are different objects; == returns false.Final Answer:true false because 127 is cached bu

[Solved] Consider this code:Integer a = 127; Integer b = 127; Integer c = 128; Integer d = 128; System.out.println(a == b); System.out.println(c == d);What is the output and why? | Java

Java - Wrapper Classes

Consider this code:

Integer a = 127;
Integer b = 127;
Integer c = 128;
Integer d = 128;
System.out.println(a == b);
System.out.println(c == d);

What is the output and why?

Afalse false because both are different objects

Btrue false because 127 is cached but 128 is not

Ctrue true because all values are autoboxed

Dfalse true because 128 is cached but 127 is not

Step-by-Step Solution

Solution:

Step 1: Recall Integer cache range
Java caches Integer objects for values from -128 to 127, so a and b reference the same object.
Step 2: Analyze comparison results
c and d are outside cache range, so they are different objects; == returns false.
Final Answer:
true false because 127 is cached but 128 is not -> Option B
Quick Check:
Integer cache affects == comparison results [OK]

Quick Trick: Integer cache range is -128 to 127 for == comparisons [OK]

Common Mistakes:

Assuming == compares values always
Ignoring cache range effect
Confusing autoboxing with caching

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Consider this code:

Step 1: Recall Integer cache range

Step 2: Analyze comparison results

Final Answer:

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