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

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


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.

Inspection Details

Available in:

IntelliJ IDEA 2023.3, Qodana for JVM 2023.3


Java, 233.SNAPSHOT

Last modified: 13 July 2023