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| Core java - Interview Questions and Answers for 'Ancestry' - 9 question(s) found - Order By Newest | ||||
 Very frequently asked in different variations. Frequently asked in Deloitte ( 2 feedback ) , HCL Tech ( 3 feedback ), TCS and Coginizant (CTS) | ||||
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| Ans. If the Object value will not change, use String Class because a String object is immutable. If the Object value can change and will only be modified from a single thread, use StringBuilder because StringBuilder is unsynchronized(means faster). If the Object value may change, and can be modified by multiple threads, use a StringBuffer because StringBuffer is thread safe(synchronized). | ||||
 Sample Code for String Sample Code for StringBuffer Sample Code for StringBuilder | ||||
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 Discuss Correct / Improve  java string class string stringbuilder stringbuffer String vs StringBuffer String vs StringBuilder String vs StringBuilder vs StringBuffer StringBuffer vs stringBuilder  Asked in 29 Companies  basic  frequent | ||||
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| Ans. OOPs or Object Oriented Programming is a Programming model which is organized around Objects instead of processes. Instead of a process calling series of processes, this model stresses on communication between objects. Objects that all self sustained, provide security by encapsulating it's members and providing abstracted interfaces over the functions it performs. OOP's facilitate the following features 1. Inheritance for Code Reuse 2. Abstraction for modularity, maintenance and agility 3. Encapsulation for security and protection 4. Polymorphism for flexibility and interfacing | ||||
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| Discuss Correct / Improve oops oops features Asked in 260 Companies basic frequent | ||||
| Frequently asked at HCL Technologies ( Based on 3 feedback ) | ||||
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| Ans. Checked exceptions are the exceptions for which compiler throws an errors if they are not checked whereas unchecked exceptions are caught during run time only and hence can't be checked. | ||||
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| Discuss Correct / Improve java exceptions checked exceptions unchecked exceptions exception handling checked vs unchecked exceptions Asked in 39 Companies basic frequent | ||||
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| Frequently asked in face to face interviews. | ||||
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| Ans. int count = 15; int[] fibonacci = new int[count]; fibonacci[0] = 0; fibonacci[1] = 1; for(int x=2; x < count; x++){ fibonacci[x] = fibonacci[x-1] + fibonacci[x-2]; } for(int x=0; x< count; x++){ System.out.print(fibonacci[x] + " "); } | ||||
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| Discuss Correct / Improve ebay fibonacci series Asked in 66 Companies basic frequent | ||||
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| Ans. Because String being an immutable object creates a new object upon each concatenation cycle. If there is any such need , we should use String Builder whose objects are mutable. | ||||
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| Discuss Correct / Improve string string immutable immutability for loop control statements loop statement Asked in 1 Companies | ||||
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| Ans. string and wrapper class objects | ||||
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| Discuss Correct / Improve immutability immutable immutability classes immutable immutability collections Asked in 3 Companies | ||||
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| Ans. Immutable objects are thread-safe so you will not have any synchronization issues.Immutable objects are good for Map keys and Set elements, since these typically do not change once created.Immutability makes it easier to write, use and reason about the code (class invariant is established once and then unchanged)Immutability makes it easier to parallelize your program as there are no conflicts among objects.The internal state of your program will be consistent even if you have exceptions.References to immutable objects can be cached as they are not going to change. | ||||
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| Discuss Correct / Improve immutable immutability classes benefits of immutable immutability classes Asked in 1 Companies | ||||
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| This question was recently asked at 'Ancestry'.This question is still unanswered. Can you please provide an answer. | ||||
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| Discuss Correct / Improve linkedlist internal implementation of linkedlist Asked in 1 Companies | ||||
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| Ans. The Java collections framework (JCF) is a set of classes and interfaces that implement commonly reusable collection data structures. Although referred to as a framework, it works in a manner of a library. The JCF provides both interfaces that define various collections and classes that implement them. | ||||
| Sample Code for Map Sample Code for HashMap Sample Code for Treemap Sample Code for set Sample Code for hashset Sample Code for treeset Sample Code for list Sample Code for arraylist Sample Code for linkedlist Sample Code for queue Sample Code for priorityqueue Sample Code for concurrenthashmap Sample Code for vector Sample Code for stack | ||||
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| Discuss Correct / Improve collections Asked in 9 Companies basic frequent | ||||
Which of the following has been introduced with Java 8 ?
