Answer Posted / ganesh

We need to override the equals method when we write our own class and we want the instance of that class to be part of some collection.

When you place the object in collection and make the manipulation on them, say sorting/searching etc.
The comparison of the object has to be done by the alogorithm.
The Algorithm uses the equals method to check for equality of two objects. Otherwise it wont be having any means to check for equality.

class Student
{
private String serialNo;
private String name;
}

two student objects with the same name cannot be the same students, but two student objects with the same serial number should the same object.

search(Student st,List a)
{
Collections.binarySearch(a,st);

}

when you want to put the objects in the hashMap, then overriding the cashCode is necessary. HashMap calls the hashCode method on the object to insert into HashMap.

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