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| Interview Questions and Answers for 'Science' - 14 question(s) found - Order By Newest | ||||
 Very frequently asked. Among first few questions in almost all interviews. Among Top 5 frequently asked questions. Frequently asked in Indian service companies (HCL,TCS,Infosys,Capgemini etc based on multiple feedback ) and Epam Systems | ||||
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| Ans. "equals" is the method of object class which is supposed to be overridden to check object equality, whereas "==" operator evaluate to see if the object handlers on the left and right are pointing to the same object in memory. x.equals(y) means the references x and y are holding objects that are equal. x==y means that the references x and y have same object. Sample code: String x = new String("str"); String y = new String("str"); System.out.println(x == y); // prints false System.out.println(x.equals(y)); // prints true | ||||
 Sample Code for equals | ||||
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 Discuss Correct / Improve  java string comparison string object class == equals object equality operator == vs equals equals vs ==  Asked in 294 Companies  basic  frequent | ||||
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| Very Frequently asked to fresh graduates and less experienced. Favorite question in Walk in drives. Frequently asked in Indian Services companies. | ||||
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| Ans. Overloading - Similar Signature but different definition , like function overloading. Overriding - Overriding the Definition of base class in the derived class. | ||||
| Sample Code for overloading Sample Code for overriding | ||||
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| Discuss Correct / Improve java oops overloading overriding oops concepts basic interview question overloading vs overriding Asked in 86 Companies basic frequent | ||||
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| Frequently asked in Cognizant (CTS) | ||||
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| Ans. Storing the state of an object in a file or other medium is called serialization. Classes can communicate only if they are built together ( as they need Byte code for communication ). What if we need to enable communication between different applications ( i.e they have been built independently or even they reside at different locations ), We need a mechanism that will transfer the Bean state to a Medium than can be transferred to the receiving application. | ||||
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| Discuss Correct / Improve java oops serialization Asked in 18 Companies basic frequent | ||||
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| Frequently asked. Among first few questions in the J2EE segment of interview. | ||||
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| Ans. Deployment Descriptor which is usually web.xml is used to specify the classes, resources and configuration of the application and how the web server uses them to serve web requests.This file is usually added to WEB-INF folder and contains following * Servlet entries and url mapping * Plugins * Some info regarding authentication / filters * Landing Page * Event Handlers | ||||
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| Discuss Correct / Improve web.xml servlets deployment descriptor Asked in 15 Companies basic frequent | ||||
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| Very frequently asked in phone and walk in interviews. | ||||
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| Ans. An interface without any method declaration is called as marker interface. there are 3 in-built interfaces in JVM i.e. serializable, clonable, remote | ||||
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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. Yes, We can call garbage collector directly but it doesn't guarantees that the gc will start executing immediately. This gc( ) method appears in both Runtime and System classes of java.lang package. | ||||
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| Discuss Correct / Improve java garbage collection java memory management jvm gc yes no Asked in 4 Companies expert | ||||
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| Ans. BlockingQueue is a Queue that supports operations that wait for the queue to become non-empty when retrieving and removing an element, and wait for space to become available in the queue when adding an element. | ||||
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| Discuss Correct / Improve blockingqueue collections java concurrent collections Asked in 10 Companies | ||||
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| Ans. When a Table Join itself , it's a Self Join. For example - we like to know the pair of department names where first dept has lesser employees than the later. Select D1.name , D2.name from Dept D1, Dept D2 where D1.employee_count < D2.employee_count | ||||
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| Discuss Correct / Improve sql joins self join self-join Pair of employee names with first having lesser salary than later Pair of department names where first dept has lesser employees than the later Asked in 26 Companies basic frequent | ||||
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| Ans. Abstraction is a process of hiding the implementation details and describing only the functionality to the user. | ||||
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| Discuss Correct / Improve bstraction oops concepts oops principle Asked in 22 Companies | ||||
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| Ans. Transient variables are variable that cannot be serialized. | ||||
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| Discuss Correct / Improve java serialization transient Asked in 15 Companies intermediate rare | ||||
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| Ans. The accessibility (public, protected, etc.) of the inner class is defined by the outer class. Just like top-level classes, an inner class can extend a class or can implement interfaces. Similarly, an inner class can be extended by other classes, and an inner interface can be implemented or extended by other classes or interfaces. An inner class can be declared final or abstract.Inner classes can have inner classes, but you will have a hard time reading or understanding such complex nesting of classes. | ||||
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| Discuss Correct / Improve java oops classes inner classes Asked in 2 Companies Basic frequent | ||||
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| Very Frequently asked. Favorite question in walkins and telephonic interviews. Usually among first few questions. Asked in different variants. Must know for intermediate and expert professionals.Among Top 10 frequently asked questions. | ||||
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| Ans. A Class must override the hashCode method if its overriding the equals method. | ||||
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| Discuss Correct / Improve java collections hashcode hash code equals collections Asked in 44 Companies intermediate frequent | ||||
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| Ans. Select Name from EMPLOYEE where ID in (Select ManagerEmployeeId from EMPLOYEE Group By ManagerEmployeeId order by count(Id) LIMIT 1) | ||||
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| Discuss Correct / Improve database sql Asked in 1 Companies | ||||
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| Ans. PATH, CLASSPATH and JAVA_HOME | ||||
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| Discuss Correct / Improve environment variables path classpath java_home Asked in 3 Companies basic frequent | ||||
Which of the following statement is not true ?
