Operators & Expressions

The Big Picture

Operators perform calculations, comparisons, and logic. Expressions combine operators and operands to produce values.

• Arithmetic: + - * / % for math operations
• Comparison: == != < > <= >= return boolean
• Logical: && || ! for combining conditions
• Bitwise: & | ^ ~ << >> >>> for bit manipulation

How It Works

Precedence determines order: * before +, comparisons before &&. Use parentheses for clarity in complex expressions.

• Short-circuit: && stops if left is false
• Integer division truncates: 7 / 2 = 3
• Use double for decimal results
• Increment: ++i (pre) vs i++ (post) differ in timing

In the Java Landscape

Java has no operator overloading (unlike C++).

• + only works for primitives and String concatenation
• Bitwise operators for flags, encryption, low-level code
• Ternary: x > 0 ? "pos" : "neg"
• instanceof checks type (pattern matching in Java 16+)
• Math.addExact() (Java 8) detects overflow

Pitfalls and Best Practices

• Use equals() for objects, not == (compares references)
• Watch division by zero - ArithmeticException for integers
• Floating-point gives Infinity/NaN instead
• Avoid side effects in complex expressions
• Integer overflow wraps silently - use exact methods
• Parentheses always clarify intent - use them liberally