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;
    ...
  }

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NonFinalFieldReferencedInHashCode

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Inspection Details
By default bundled with:	IntelliJ IDEA 2024.3, Qodana for JVM 2024.3,
Can be installed with plugin:	Java, 243.23126

Last modified: 03 December 2024