Repeated Cast of Same Object

ID

java.repeated_cast_same_object

Severity

low

Remediation Complexity

trivial

Remediation Risk

low

Remediation Effort

low

Resource

Efficiency

Language

Java

Tags

efficiency

Description

Reports casting the same expression to the same type more than once in a method body.

Rationale

Casting the same object to the same type multiple times is redundant. Each cast adds visual noise and, depending on the JIT compiler, may incur a small runtime cost for the type check. More importantly, repeated casts are a readability problem: they signal that the code would benefit from a local variable holding the cast result.

// Bad -- repeated cast
String a = ((String) obj).trim();
String b = ((String) obj).toLowerCase();

Remediation

Cast once, store the result in a local variable, and reuse it.

// Good -- cast once, reuse
String s = (String) obj;
String a = s.trim();
String b = s.toLowerCase();

References