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Programmers frequently make errors regarding the precedence of operators because of the unintuitive low-precedence levels of &, |, ^, <<, and >>. Avoid mistakes regarding precedence through the suitable use of parentheses. This can , which also improves code readability. The precedence of operations by the order of the subclauses are defined in the Java Tutorials [Tutorials 2008].

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This expression gets evaluated as follows, resulting in the value 0.:

x & (1337 - 1337)

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This compliant solution uses parentheses to ensure that the expression evaluates as intended.:

public static final int MASK = 1337;
public static final int OFFSET = -1337;

public static int computeCode(int x) {
  return (x & MASK) + OFFSET;
}

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In this noncompliant code example, the intent is to add to the string "value=".:

public class Test{
    public static void main(String[] args) {
        String s = null;
        System.out.println("value=" + s == null? 0 : 1); // prints "1"
    }
}

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This compliant solution uses parentheses to ensure that the expression evaluates as intended.:

public class Test{
    public static void main(String[] args) {
        String s = null;
        System.out.println("value=" + (s == null? 0 : 1)); // prints "value=0" as expected
    }
}

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Parentheses may be omitted from mathematical expressions that follow the algebraic precedence rules. For instance, consider the following expression:

x + y * z

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Related Guidelines

Bibliography

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