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Arithmetic Expressions
An arithmetic expression is a combination of variables, constants, and operators arranged as per the syntax of the language. Java can handle any complex mathematical expressions.
Evaluation of Expressions
Expressions are evaluated using an assignment statement of the form
variable = expression;
Variable is any valid Java variable name. When the statement is encountered, the expression is evaluated first and the result then replaces the previous value of the variable on the left-hand side. All variables used in the expression must be assigned values before evaluation is attempted.
Precedence of Arithmetic Operators

An arithmetic expression without any parentheses will be evaluated from left to right using the rules of
precedence of operators. There are two distinct priority levels of arithmetic operators in Java:

High priority * / %
Low priority + -
The basic evaluation procedure includes two left-to-right passes through the expression. During the first pass, the high priority operators (if any) are applied as they are encountered. During the second pass, the low priority operators (if any) are applied as they are encountered.
The order of evaluation can be changed by introducing parentheses into an expression.

Whenever the parentheses are used, the expressions within parentheses assume highest priority. If
two or more sets of parentheses appear one after another, the expression contained in the left-most set is evaluated first and the right-most in the last.
Operator Precedence and Associativity

Each operator in Java has a precedence associated with it. This precedence is used to determine how an expression involving more than one operator is evaluated. The operators at the higher level of precedence are evaluated first. The operators of the same precedence are evaluated either from left to right or from right to left, depending on the level. This is known as the associativity property of an operator.