Dangling Else

ID

java.dangling_else

Severity

info

Remediation Complexity

medium

Remediation Risk

low

Remediation Effort

medium

Resource

Code Smell

Language

Java

Tags

CWE:483, code-style, reliability

Description

Reports if statements where an unbraced then-block contains a nested if with an else clause. The else binds to the inner if by language rules, but the programmer may have intended it for the outer if. Adding braces eliminates the ambiguity.

Rationale

The dangling-else ambiguity occurs when nested if statements lack braces. The else always associates with the nearest if, which may not match the indentation or the developer’s intent:

if (a)
    if (b)
        doX();
    else           // Binds to 'if (b)', not 'if (a)'
        doY();

Remediation

Use braces to make the intended structure explicit:

if (a) {
    if (b) {
        doX();
    } else {
        doY();     // Now clearly "a is true but b is false"
    }
}

References