Object Model Violation: Just One of equals() and hashCode() Defined

Last revision (mm/dd/yy): //

Vulnerabilities Table of Contents

Description
This class overrides only one of equals and hashCode.

Java objects are expected to obey a number of invariants related to equality. One of these invariants is that equal objects must have equal hashcodes. In other words, if a.equals(b) == true then a.hashCode == b.hashCode.

Failure to uphold this invariant is likely to cause trouble if objects of this class are stored in a collection. If the objects of the class in question are used as a key in a Hashtable or if they are inserted into a Map or Set, it is critical that equal objects have equal hashcodes.

Risk Factors

 * Talk about the factors that make this vulnerability likely or unlikely to actually happen
 * Discuss the technical impact of a successful exploit of this vulnerability
 * Consider the likely [business impacts] of a successful attack

Examples
The following class overrides equals but not hashCode.

public class halfway { public boolean equals(Object obj) { ...   }  }

Related Attacks

 * Attack 1
 * Attack 2

Related Vulnerabilities

 * Vulnerability 1
 * Vulnerabiltiy 2

Related Controls

 * Control 1
 * Control 2

Related Technical Impacts

 * Technical Impact 1
 * Technical Impact 2