Object instantiation inside 'equals()' or 'hashCode()'

Reports construction of (temporary) new objects inside equals(), hashCode(), compareTo(), and Comparator.compare() methods.

Besides constructor invocations, new objects can also be created by autoboxing or iterator creation inside a foreach statement. This can cause performance problems, for example, when objects are added to a Set or Map, where these methods will be called often.

The inspection will not report when the objects are created in a throw or assert statement.

Example:

  class Person {
    private String name;
    private int age;

    public boolean equals(Object o) {
      return Arrays.equals(new Object[] {name, age}, new Object[] {((Foo)o).name, ((Foo)o).age});
    }

    public int hashCode() {
      return (name + age).hashCode();
    }
  }

In this example, two additional arrays are created inside equals(), usages of age field require boxing, and name + age implicitly creates a new string.

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.

ObjectInstantiationInEqualsHashCode

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 | Performance

Suppressing Inspection

You can suppress this inspection by placing the following comment marker before the code fragment where you no longer want messages from this inspection to appear:

//noinspection ObjectInstantiationInEqualsHashCode

More detailed instructions as well as other ways and options that you have can be found in the product documentation:

IntelliJ IDEA 2025.2

Inspection Details
By default bundled with:	IntelliJ IDEA 2025.2, Qodana for JVM 2025.2,

Last modified: 18 September 2025