'clone()' should have return type equal to the class it contains

Reports clone() methods with return types different from the class they're located in.

Often a clone() method will have a return type of java.lang.Object, which makes it harder to use by its clients. Effective Java (the second and third editions) recommends making the return type of the clone() method the same as the class type of the object it returns.

Example:

  class Foo implements Cloneable {
    public Object clone() {
      try {
        return super.clone();
      } catch (CloneNotSupportedException e) {
        throw new AssertionError();
      }
    }
  }

After the quick-fix is applied:

  class Foo implements Cloneable {
    public Foo clone() {
      try {
        return (Foo)super.clone();
      } catch (CloneNotSupportedException e) {
        throw new AssertionError();
      }
    }
  }

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.

CloneReturnsClassType

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 | Cloning issues

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