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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.
Ans. It's a feature to lazily initialize dependencies , relationship and associations from the Database. Any related references marked as @OneToMany or @ManyToMany are loaded lazily i.e when they are accessed and not when the parent is loaded.
Feature to load all objects and relationships in advance before they can be used
Feature to not load dependencies and relationship in advance and load when required
Feature to not load the dependencies and relationships at all
Which of the following is not the benefit of Lazy Initialization in Hibernate ?
Laod When required provides better performance
Object stays lighter
Less number of Database calls
Less load on Database
Very frequently asked. Usually followed by questions related to private constructor and synchronized access. Frequently asked in JPMorgan and TCS (Based on 2 feedback)
Ans. Exception thrown by the application is we try to access an element using an index which is not within the range of array i.e lower than 0 or greater than the size of the array.
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