Operators and expressions

In Java, operators are symbols that perform specific operations on one or more operands (variables, constants, or literals) and produce a result. Expressions, on the other hand, are combinations of operators, operands, and method invocations that evaluate to a single value.

Here are some commonly used operators in Java:

1. Arithmetic Operators:
   • Addition (+): Adds two operands.
   • Subtraction (-): Subtracts the second operand from the first.
   • Multiplication (*): Multiplies two operands.
   • Division (/): Divides the first operand by the second.
   • Modulus (%): Returns the remainder of the division.
   • Increment (++) and Decrement (–): Increases or decreases the value of an operand by 1.
2. Relational Operators:
   • Equal to (==): Checks if two operands are equal.
   • Not equal to (!=): Checks if two operands are not equal.
   • Greater than (>): Checks if the first operand is greater than the second.
   • Less than (<): Checks if the first operand is less than the second.
   • Greater than or equal to (>=): Checks if the first operand is greater than or equal to the second.
   • Less than or equal to (<=): Checks if the first operand is less than or equal to the second.
3. Logical Operators:
   • Logical AND (&&): Returns true if both operands are true.
   • Logical OR (||): Returns true if either of the operands is true.
   • Logical NOT (!): Reverses the logical state of the operand.
4. Assignment Operators:
   • Simple Assignment (=): Assigns a value to a variable.
   • Compound Assignment (+=, -=, *=, /=): Performs an operation and assigns the result to the variable.
5. Bitwise Operators:
   • Bitwise AND (&): Performs a bitwise AND operation.
   • Bitwise OR (|): Performs a bitwise OR operation.
   • Bitwise XOR (^): Performs a bitwise exclusive OR operation.
   • Bitwise complement (~): Inverts the bits of the operand.
   • Left shift (<<) and Right shift (>>): Shifts the bits of the operand to the left or right.

These are just a few examples of operators in Java. There are additional operators such as the ternary operator (?:), instanceof operator, bitwise shift operators (<<, >>>, <<<), etc.

Expressions are built using operators and operands. An expression can involve arithmetic calculations, logical comparisons, method invocations, and variable assignments. For example:

int x = 5;
int y = 10;
int sum = x + y;          // Arithmetic expression
boolean isTrue = x > y;   // Relational expression
boolean result = (x > 0) && (y < 20);  // Logical expression

In the examples above, the expressions x + y, x > y, and (x > 0) && (y < 20) evaluate to a single value.