CODEWITHSUNDEEP
javastringclassobject
Karish Karish
Karish Karish

Reputation: 269

Comparing 2 objects from different classes java

Is it possible to compare 2 object from 2 different classes.

lets say i have an vector which adds all the objects from class A. i want to compare some string to the elements of the vector.

Example:

if(string.equals(vector.get(i)))

is this possible ?

Upvotes: 0

Views: 2367

Answers (5)

NPE
NPE

Reputation: 500207

Yes, you can call equals(). However, any reasonable implementation of SomeClass.equals() would return false if the argument is of a different class (other than perhaps a subclass).

If string is an instance of java.lang.String, this behaviour is specifically guaranteed:

The result is true if and only if the argument is not null and is a String object that represents the same sequence of characters as this object.

Upvotes: 3

lynks
lynks

Reputation: 5689

It's perfectly valid to write something like;

public class MyClass {
    public boolean equals(Object o) {
        if(o instanceof SomeUnrelatedClass) return true;
        return false;
    }
}

But it is not advisable, as least I would try to avoid it. It would make handling MyClass objects a little strange, for example putting them into a hash-based collection.

Upvotes: 0

Marius Danila
Marius Danila

Reputation: 10411

If the list's elements have type other than String it will always return false. From the String documentation for method equals:

Compares this string to the specified object. The result is true if and only if the argument is not null and is a String object that represents the same sequence of characters as this object.

This is generally true for the method equals - it will or should return true only in the eventuality that the compared object is of the same class or a subclass of the former.

Upvotes: 0

CodeDreamer
CodeDreamer

Reputation: 444

Equals method of an object can take any other object. However, it would be up to the implementation to not return true when comparing an apple with an orange

Upvotes: 0

zkar
zkar

Reputation: 61

Your objects are at least in the class Object, and thus (at least partly) in the same class.

Upvotes: 1

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