STUDYECRAT Java : Operators
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Java Operators
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★ Java Operators: Key Interview Points
1. Operator Precedence
System.out.println(5 + 3 * 2); // 11 (not 16)
// Order: () → * / % → + - → << >> → == != → & → ^ → | → && → ||
// Order: () → * / % → + - → << >> → == != → & → ^ → | → && → ||
- Highest: Parentheses
() - Common Trap:
+has lower precedence than*
2. Prefix vs Postfix Increment
int x = 5;
System.out.println(x++); // 5 (postfix: use then increment)
System.out.println(++x); // 7 (prefix: increment then use)
System.out.println(x++); // 5 (postfix: use then increment)
System.out.println(++x); // 7 (prefix: increment then use)
Critical in loop conditions and complex expressions.
3. Short-Circuit Evaluation
&& and ||
if (false && (5/0 == 0))
// No error: skips 2nd condition
Non-Short-Circuit
& and |
// Always evaluate both sides
4. Bitwise Magic
System.out.println(5 & 3); // 1 (AND)
System.out.println(5 | 3); // 7 (OR)
System.out.println(~5); // -6 (NOT)
System.out.println(5 << 2); // 20 (left shift = *4)
System.out.println(5 | 3); // 7 (OR)
System.out.println(~5); // -6 (NOT)
System.out.println(5 << 2); // 20 (left shift = *4)
- Interview Favorite: Swapping variables without temp:
x = x ^ y; y = x ^ y; x = x ^ y;
5. Compound Assignment Gotchas
int x = 10;
x += x -= x *= x; // -80 (right-to-left evaluation)
byte b = 5;
b = b + 2; // Error
b += 2; // Valid (auto-casts)
x += x -= x *= x; // -80 (right-to-left evaluation)
byte b = 5;
b = b + 2; // Error
b += 2; // Valid (auto-casts)
💡 Pro Interview Tip
90% of interview operator questions test these 5 concepts.
Practice writing the outputs of nested operators like x = ++x + x++ on paper -
whiteboard coding often focuses on these!
