In Java 16 records represent a brief notation for immutable data structures. Records have autogenerated implementations for constructors with all
parameters, getters, equals, hashcode and toString. Although these methods can still be overridden
inside records, there is no use to do so if no special logic is required.
This rule reports an issue on empty compact constructors, trivial canonical constructors and simple getter methods with no additional logic.
Noncompliant code example
record Person(String name, int age) {
Person(String name, int age) { // Noncompliant, already autogenerated
this.name = name;
this.age = age;
}
}
record Person(String name, int age) {
Person { // Noncompliant, no need for empty compact constructor
}
public String name() { // Noncompliant, already autogenerated
return name;
}
}
Compliant solution
record Person(String name, int age) { } // Compliant
record Person(String name, int age) {
Person(String name, int age) { // Compliant
this.name = name.toLowerCase(Locale.ROOT);
this.age = age;
}
}
record Person(String name, int age) {
Person { // Compliant
if (age < 0) {
throw new IllegalArgumentException("Negative age");
}
}
public String name() { // Compliant
return name.toUpperCase(Locale.ROOT);
}
}
