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| Interview Questions and Answers for 'Pramati Technologies' - 4 question(s) found - Order By Newest | ||||
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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 arraylist vs linkedlist  Asked in 61 Companies  Basic  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 5 Companies intermediate frequent | ||||
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| Ans. 1. HashSet doesnt maintain its elements in any specific order and is all random whereas TreeSet maintains elements in natural order 9 order defined by the equals method of TreeSet element type ) 2. TreeSet doesnt allow null elements whereas HashMap does. 3. As TreeSet orders elements and is hence insertion is comparatively slower. 4. HashSet performs basic operations like add(), remove(), contains(), size() etc. in a constant size time. A TreeSet performs these operations at the order of log(n) time. 5. HashMap in Java internally backs a HashSet. A NavigableMap backs a TreeSet internally. | ||||
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| 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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What will be the output of exceuting main method ?
