Other Java Interview questions articles from Javarevisited blog. Why multiple inheritances are not supported in Java. Why wait and notify method called from synchronized block or method.
Difference between start and run method in Java. Why the main method is static in Java. Difference between transient and volatile in Java.
Share to Twitter Share to Facebook. Labels: core java , core java interview question , programming. November 27, at PM Anonymous said January 15, at AM Anonymous said July 1, at PM javin paul said July 3, at AM Ajay Thakur said On line 3, the individual who wrote this wrote: "behaves identical for every object but equals is method" This should be: "behaves identical for every object but equals is a method" November 4, at PM.
Newer Post Older Post Home. Subscribe to: Post Comments Atom. Subscribe for Discounts and Updates Follow. Search This Blog. Interview Questions core java interview question data structure and algorithm 78 Coding Interview Question 75 interview questions 70 design patterns 35 SQL Interview Questions 34 object oriented programming 34 thread interview questions 30 spring interview questions 28 collections interview questions 25 database interview questions 16 servlet interview questions 15 Programming interview question 6 hibernate interview questions 6.
How to design a vending machine in Java? How HashMap works in Java? Why String is Immutable in Java? Translate This Blog. How to Solve java. ClassNotFoundException: org How to use var to declare local variables in Java? Example What is SuppressWarnings annotation in Java? Difference between Process and Thread in Java - Ex Spring Transactional Annotation Example - How to How to create thread safe Singleton in Java - Java Add a comment.
Active Oldest Votes. In general, the answer to your question is "yes", but If a class does not override the equals method, then it defaults to the equals Object o method of the closest parent class that has overridden this method. If no parent classes have provided an override, then it defaults to the method from the ultimate parent class, Object, and so you're left with the Object equals Object o method. Thus you will be testing for object equality and not functional equality. Always remember to override hashCode if you override equals so as not to "break the contract".
As per the API, the result returned from the hashCode method for two objects must be the same if their equals methods show that they are equivalent. The converse is not necessarily true. Improve this answer. JSK print the values of d1 and d2 and I think you'll see why you're returning false. BoDidely I figured it out. It was because all the wrapper classes are immutable.
Unrelated: Today I put up a meta question meta. The feedback I received felt pretty much "you are doing the totally wrong thing". Now I am simply wondering how you look at this?
Do you have "generic" messages in your quiver, or do you write solely specific comments in such cases? With respect to the String class: The equals method compares the "value" inside String instances on the heap irrespective if the two object references refer to the same String instance or not. As with any explanation, let it sink in. I hope this clears things up a bit. Community Bot 1 1 1 silver badge.
Jacques Colmenero Jacques Colmenero 1, 1 1 gold badge 8 8 silver badges 3 3 bronze badges. Thread necromancy, I know It won't always, and it's certainly bad practice, but it's a common mistake, particularly from people coming from other languages. To add on to Tonio's comment. String build from string literal will be added to something called the String constant pool , e. But if they were constructed via the String constructor , e.
Cazumbi Cazumbi 2, 1 1 gold badge 27 27 silver badges 24 24 bronze badges. Interesting example. Different perspective from the above answers. Best answer in my opinion, as it's clearer than the other full-text answers without losing the explanation if you undertand class and static concepts, of course — Carrm.
Now you see the identityHashCode mango is equal to identityHashCode mango2 But it is not equal to identityHashCode mango3 Even though all the string variables - mango, mango2 and mango3 - have the same value, which is "mango", identityHashCode is still not the same for all. Yoon5oo 5 5 silver badges 11 11 bronze badges. Mohanraj Mohanraj 3, 1 1 gold badge 23 23 silver badges 17 17 bronze badges.
It will reused the same string "adc". Test it in a sandbox, it will return true for both. JohnathanLogan I guess its due to string interning. Now I have changed to "new String "abc" ". Hope now there won't be any issues. Thanks for informing. Your answer is only valid for String objects and because String overrides equals to return true if the "represents the same sequence of characters".
The equals method compares the objects. AADProgramming 5, 11 11 gold badges 34 34 silver badges 57 57 bronze badges. Andrew Carr Andrew Carr 6 6 silver badges 16 16 bronze badges. Shanu Gupta 3, 2 2 gold badges 16 16 silver badges 28 28 bronze badges. Simple and easiest answer — gulab patel. Sarat Chandra Sarat Chandra 4, 24 24 silver badges 27 27 bronze badges. Simple and best explanation — Sritam Jagadev. They are aliases; System. Tadele Ayelegn Tadele Ayelegn 3, 1 1 gold badge 29 29 silver badges 27 27 bronze badges.
For example : System. Miriam Farber Otherwise, we will get compile-time error. If all the contents of both the strings are same then it returns true. If all characters are not matched then it returns false. In the above example, we are creating 3 Thread objects and 2 String objects. Both the objects contain the same String i. This article is contributed by Veturi Lakshmi Prathyusha. If you like GeeksforGeeks and would like to contribute, you can also write an article using write.
See your article appearing on the GeeksforGeeks main page and help other Geeks. Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above. Skip to content. Change Language.
0コメント