Duplicate condition

Reports duplicate conditions in && and || expressions and branches of if statements. While sometimes duplicate conditions are intended, in most cases they the result of an oversight.

Example:

boolean result = digit1 != digit2 || digit1 != digit2;

Locating this inspection

By ID

Can be used to locate inspection in e.g. Qodana configuration files, where you can quickly enable or disable it, or adjust its settings.

DuplicateCondition

Via Settings dialog

Path to the inspection settings via IntelliJ Platform IDE Settings dialog, when you need to adjust inspection settings directly from your IDE.

Settings or Preferences | Editor | Inspections | Java | Control flow issues

To ignore conditions that may produce side effects, use the Ignore conditions with side effects option. Disabling this option may lead to false-positives, for example, when the same method returns different values on subsequent invocations.

Example:

  native boolean unknownMethod();
  
  ...
  
  if (unknownMethod() || unknownMethod()) {
    System.out.println("Got it");
  }

Due to possible side effects of unknownMethod() (on the example), the warning will only be triggered if the Ignore conditions with side effects option is disabled.

Inspection options

Here you can find the description of settings available for the Duplicate condition inspection, and the reference of their default values.

Ignore conditions with possible side effects: Default: Selected

Availability

By default bundled with: IntelliJ IDEA 2024.1, Qodana for JVM 2024.1,
Can be installed with plugin: Java, 241.18072

Last modified: 18 June 2024