Core java - Interview Questions and Answers for 'Naggaro' - 3 question(s) found - Order By Newest Basic and Very Frequently asked. Ans. Polymorphism means the condition of occurring in several different forms. Sample Code for overloading Sample Code for overriding Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve Asked in 108 Companies Basic frequent Related Questions What are points to consider in terms of access modifier when we are overriding any method? If everything is an object , Cant we declare every object as Why do we need polymorphism in Java ? How does java identifies which method to be called in method overriding or runtime polymorphism, when both methods share the same name and signature ? Shouldn't we make a class with all static members is its just expected to be executed as a standalone program with just one thread. Moreover Lets assume that there is no runtime Polymorphism required and there is no need for serialization ? Is this Polymorphism ? When are static and instance methods resolved ? During compile time or Runtime ? Which of the following is not the difference between Singleton and Static class ( Class with static members only ) ? Which of the following do you think is the primary reason you would never use a static class even the application doesn't need multiple requests or threads ? Frequently asked in all types of companies especially Indian Services companies. Frequently asked in CTS (Based on 2 feedback) Q2. What is the use of hashcode in Java ? Core Java
Ans. Hashcode is used for bucketing in Hash implementations like HashMap, HashTable, HashSet etc. The value received from hashcode() is used as bucket number for storing elements. This bucket number is the address of the element inside the set/map. when you do contains() then it will take the hashcode of the element, then look for the bucket where hashcode points to and if more than 1 element is found in the same bucket (multiple objects can have the same hashcode) then it uses the equals() method to evaluate if object are equal, and then decide if contain() is true or false, or decide if element could be added in the set or not. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve Asked in 33 Companies intermediate frequent Related Questions Which String class does not override the equals() and hashCode() methods, inheriting them directly from class Object? Write a class and override the equals and hashcode method ? How many threads can access a concurrent hashmap when the hashcode is overridden and always returns a zero. Q3. Write a method to check if input String is Palindrome? Core Java
Ans. private static boolean isPalindrome(String str) { Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve Asked in 38 Companies Basic frequent Related Questions Which keyword is used to provide explicit access of a code block to single thread ? How does volatile affect code optimization by compiler? Will this code give error if i try to add two heterogeneous elements in the arraylist. ? and Why ? What is the difference between the following two code lines ? Which String class does not override the equals() and hashCode() methods, inheriting them directly from class Object? If arrays cannot be resized , Why is this code valid Will the static block be executed in the following code ? Why ? If you are given a choice to implement the code to either Insert a Record or Update if already exist, Which approach will you follow ? Which of the following is not the advantage of Mocking frameworks ? How can we make sure that a code segment gets executed even in case of uncatched exceptions ?
More than 3000 questions in repository.
Basic and Very Frequently asked.
polymorphism object oriented programming (oops) oops concepts oops concepts 
Try 2 Question(s) Test
Static Polymorphic in Java is achieved through .. 
Related Questions