Non-final field referenced in 'hashCode()'

Reports implementations of hashCode() that access non-final variables.

Such access may result in hashCode() returning different values at different points in the object's lifecycle, which may in turn cause problems when using the standard collections classes.

Example:

  class Drink {
    String name;
    Drink(String name) { this.name = name; }
    @Override public int hashCode() {
      return Objects.hash(name); //warning
    }
  }
  ...
    Drink coffee = new Drink("Coffee");
    priceMap.put(coffee, 10.0);
    coffee.name = "Tea";
    double coffeePrice = priceMap.get(coffee); //not found

A quick-fix is suggested to make the field final:

  class Drink {
    final String name;
    ...
  }

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.

HashCodeUsesNonFinalVariable

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 | Probable bugs

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