The following code fragment shows the result of overriding the equals() and hashCode() methods: If the overrides for equals() and hashCode() methods already exist in the class, you will be prompted whether you want to delete them before generating new ones. This optional step helps the generated code avoid checks for null and thus improves performance. Select the fields that contain non-null values. You can choose only from fields that were selected on the previous step (for determining equality). Select the fields to use for calculating the hash code value. Select the fields that should be used to determine equality, and click Next. Select checkboxes if you want to accept subclasses and use getters during code generation. You can also click to open the Templates dialog, where you can select an existing template or create a custom template. Select a velocity template from the Template list. In the Generate popup, click equals() and hashCode(). Generate equals() and hashCode() for a classįrom the Code menu, click Generate Alt+Insert. For more information, refer to the API specification for the Object class. It is generally necessary to override the hashCode() method if you override equals() because the contract for hashCode() is that it must produce the same result for objects that are equal. The hash code must not change during one execution of the application but may change between executions. Public int hashCode() returns the hash code value of the object on which this method is invoked. By default, this means that two objects are stored in the same memory address. Public boolean equals(Object obj) returns true if the object passed to it as the argument is equal to the object on which this method is invoked. The Java super class provides two methods for comparing objects: } Generate equals() and hashCode() methods
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