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Solution - Interview Questions and Answers for 'Oracle' - 7 question(s) found - Order By Newest | ||||
Frequently asked question in companies using Hibernate. | ||||
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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. | ||||
Sample Code for Lazy Initialization | ||||
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Like Discuss Correct / Improve  hibernate   lazy loading hibernate   lazy initialization hibernate   architecture Asked in 77 Companies Basic   frequent | ||||
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Basic and Very Frequently asked. | ||||
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Ans. Polymorphism means the condition of occurring in several different forms. Polymorphism in Java is achieved in two manners 1. Static polymorphism is the polymorphic resolution identified at compile time and is achieved through function overloading whereas 2. Dynamic polymorphism is the polymorphic resolution identified at runtime and is achieved through method overriding. | ||||
Sample Code for overloading Sample Code for overriding | ||||
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Like Discuss Correct / Improve  polymorphism  object oriented programming (oops)  oops concepts  oops concepts Asked in 108 Companies Basic   frequent | ||||
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Advanced level question frequently asked in US based companies. Recently asked in EMC and Intuit. | ||||
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Ans. Simplest implementation we can have is a List wherein we can place ordered words and hence can perform Binary Search. Other implementation with better search performance is to use HashMap with key as first character of the word and value as a LinkedList. Further level up, we can have linked Hashmaps like , hashmap { a ( key ) -> hashmap (key-aa , value (hashmap(key-aaa,value) b ( key ) -> hashmap (key-ba , value (hashmap(key-baa,value) .................................................................................... z( key ) -> hashmap (key-za , value (hashmap(key-zaa,value) } upto n levels ( where n is the average size of the word in dictionary. | ||||
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Like Discuss Correct / Improve  java   collections   hashmap   binary search   search algorithm   advanced   architecture   data structure Asked in 6 Companies   frequent | ||||
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Frequently asked to fresh graduates. | ||||
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Ans. ACID stands for Atomicity, Consistency, Isolation, Durability is a set of properties of database transactions. Atomicity means all or nothing. i.e parts of a transaction shouldn't commit if any one of them fails. Either the whole transaction should succeed or it should be complete rollback. Consistency means that any transaction should lead database from one stabe state to another. Isolation means that the execution of transaction results in a system state that would be obtained if transactions were executed serially. Durability means that when a transaction is committed it forms the permanent state of database. | ||||
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Like Discuss Correct / Improve  database  acid Asked in 7 Companies Intermediate | ||||
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Frequently asked in high end product companies. Frequently asked in Deloitte. | ||||
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Ans. https://medium.com/javarevisited/internal-working-of-hashmap-in-java-97aeac3c7beb#:~:text=HashMap%20internally%20uses%20HashTable%20implementation,the%20entries%20into%20the%20map. | ||||
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Like Discuss Correct / Improve  hashmap  collections  hashmap internal implementation Asked in 20 Companies expert   frequent | ||||
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Ans. Vectors are synchronized whereas Array lists are not. | ||||
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Like Discuss Correct / Improve  java   basic interview question   vector   arraylist   collections   synchronization   vector vs arraylist Asked in 35 Companies basic   frequent | ||||
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Ans. A trigger is a special kind of stored procedure that automatically gets executed upon an event in the database server. | ||||
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Like Discuss Correct / Improve  database   trigger Asked in 10 Companies basic   frequent | ||||