'clone()' does not declare 'CloneNotSupportedException'

Reports clone() methods that do not declare throws CloneNotSupportedException.

If throws CloneNotSupportedException is not declared, the method's subclasses will not be able to prohibit cloning in the standard way. This inspection does not report clone() methods declared final and clone() methods on final classes.

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.

CloneDeclaresCloneNotSupported

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

Configure the inspection:

Use the Only warn on 'protected' clone methods option to indicate that this inspection should only warn on protected clone() methods. The Effective Java book (second and third edition) recommends omitting the CloneNotSupportedException declaration on public methods, because the methods that do not throw checked exceptions are easier to use.

Example:

  public class Example implements Cloneable {
    // method doesn't declare 'throws CloneNotSupportedException'
    protected Object clone() {
        try {
            return super.clone();
        } catch (CloneNotSupportedException e) {
            return null;
        }
    }
  }

Inspection options

Here you can find the description of settings available for the 'clone()' does not declare 'CloneNotSupportedException' inspection, and the reference of their default values.

Only warn on 'protected' clone methods: Default: Selected

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