How to check if 2 Class instances are the same

Question

For example I have a class Fruit. I create 2 instances: ``` Fruit apple = new Fruit("apple"); Fruit orange = new Fruit("orange"); ``` The value of the 2 instances are not the same thus I am looking for the answer to be false. I override the .equals() method and wrote the following method to do the test: ``` @Override public boolean equals(Object otherObject){ if(otherObject instanceof Fruit){ return true; } return false; } if(apple.equals(orange)) System.out.println("true"); else System.out.println("false"); ``` The above method gives me the answer as true. From my understanding, this is a correct response since this simply tests if they both belongs to the same Class which is true. But I can't get around to testing the values of the instances itself. Please advice. Thanks.

Accepted Answer

You should have included your `Fruit` class, but here is one way

```
static class Fruit {
  private String name;

public Fruit(String name) {
    this.name = name;
  }

@Override
  public boolean equals(Object otherObject) {
    // check for reference equality.
    if (this == otherObject) {
      return true;
    }
    if (otherObject instanceof Fruit) {
      Fruit that = (Fruit) otherObject;
      // Check for name equality.
      return (name == null && that.name == null)
          || name.equals(that.name);
    }
    return false;
  }
}

public static void main(String[] args) {
  Fruit apple = new Fruit("apple");
  Fruit apple2 = new Fruit("apple");

Fruit orange = new Fruit("orange");

if (apple.equals(orange))
    System.out.println("true");
  else
    System.out.println("false");

// You can also use the shorter
  System.out.println(apple.equals(apple2));
}
```

Outputs

```
false
true
```

How to check if 2 Class instances are the same

Solution

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