In records, the default behavior of the equals() method is to check the equality by field values. This works well for primitive fields
or fields, whose type overrides equals(), but this behavior doesn’t work as expected for array fields.
By default, array fields are compared by their reference, and overriding equals() is highly appreciated to achieve the deep equality
check. The same strategy applies to hashCode() and toString() methods.
This rule reports an issue if a record class has an array field and is not overriding equals(), hashCode() or
toString() methods.
Noncompliant code example
record Person(String[] names, int age) {} // Noncompliant
Compliant solution
record Person(String[] names, int age) {
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
Person person = (Person) o;
return age == person.age && Arrays.equals(names, person.names);
}
@Override
public int hashCode() {
int result = Objects.hash(age);
result = 31 * result + Arrays.hashCode(names);
return result;
}
@Override
public String toString() {
return "Person{" +
"names=" + Arrays.toString(names) +
", age=" + age +
'}';
}
}
