'equals()' between objects of inconvertible types

Reports calls to equals() where the target and argument are of incompatible types.

While such a call might theoretically be useful, most likely it is a bug.

Example:

new HashSet<String>().equals(new TreeSet<Integer>());

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.

EqualsBetweenInconvertibleTypes

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 | Probable bugs

Inspection options

Here you can find the description of settings available for the 'equals()' between objects of inconvertible types inspection, and the reference of their default values.

Warn if no mutual subclass found: Default: Selected

Inspection Details
By default bundled with:	IntelliJ IDEA 2024.3, Qodana for JVM 2024.3,
Can be installed with plugin:	Java, 243.26483

01 April 2025