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Search Interview Questions |  3273 questions in repository. There are more than 200 unanswered questions. Click here and help us by providing the answer. Have a video suggestion. Click Correct / Improve and please let us know. |
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| Core java - Interview Questions and Answers for 'Chase' - 6 question(s) found - Order By Newest | |||||
 Very frequently asked in different variations. Frequently asked in Deloitte ( 2 feedback ) , HCL Tech ( 3 feedback ) 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  Asked in 27 Companies  basic  frequent | |||||
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| Very frequently asked. Favorite question in Walk in Drive of many Indian service companies. | |||||
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| Ans. Underlying data structure for ArrayList is Array whereas LinkedList is the linked list and hence have following differences - 1. ArrayList needs continuous memory locations and hence need to be moved to a bigger space if new elements are to be added to a filled array which is not required for LinkedList. 2. Removal and Insertion at specific place in ArrayList requires moving all elements and hence leads to O(n) insertions and removal whereas its constant O(1) for LinkedList. 3. Random access using index in ArrayList is faster than LinkedList which requires traversing the complete list through references. 4. Though Linear Search takes Similar Time for both, Binary Search using LinkedList requires creating new Model called Binary Search Tree which is slower but offers constant time insertion and deletion. 5. For a set of integers you want to sort using quicksort, it's probably faster to use an array; for a set of large structures you want to sort using selection sort, a linked list will be faster. | |||||
| Sample Code for ArrayList Sample Code for LinkedList | |||||
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| Discuss Correct / Improve collections java data structures arraylist linkedlist Asked in 61 Companies Basic frequent | |||||
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| Very frequently asked across all types of companies. | |||||
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| Ans. Hashtable is synchronized whereas HashMap is not.HashMap allows null values whereas Hashtable doesnt allow null values. | |||||
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| Discuss Correct / Improve java collections hashmap map hashtable basic interview question ebay tcs hcl technologies infosys technologies Asked in 13 Companies basic frequent | |||||
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| Very frequently asked in phone and walk in interviews. | |||||
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| Ans. These are the interfaces which have no declared methods.Serializable and cloneable are marker interfaces. | |||||
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| Discuss Correct / Improve java oops interfaces marker interface serializable clonable Asked in 21 Companies intermediate frequent | |||||
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| Ans. We can make a class immutable by 1. Making all methods and variables as private. 2. Setting variables within constructor. Public Class ImmutableClass{ private int member; ImmutableClass(int var){ member=var; } } and then we can initialize the object of the class as ImmutableClass immutableObject = new ImmutableClass(5); Now all members being private , you cant change the state of the object. | |||||
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| Discuss Correct / Improve java oops immutable immutability immutable immutability class technical lead Asked in 4 Companies intermediate frequent | |||||
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| Very frequently asked. Usually difference between String,StringBuffer and StringBuilder is asked in different variations. | |||||
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| Ans. StringBuffer is synchronized whereas StringBuilder is not. | |||||
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| Discuss Correct / Improve java string stringbuffer string class stringbuilder synchronized basic interview question infosys technologies Asked in 17 Companies basic frequent | |||||
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Which of the following has been introduced with Java 8 ?
