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Core java - Interview Questions and Answers for 'Adp' - 6 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 )
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
Ans. ArrayList are implemented in memory as arrays and hence allows fast retrieval through indices but are costly if new elements are to be inserted in between other elements. LinkedList allows for constant-time insertions or removals using iterators, but only sequential access of elements
1. Retrieval - If Elements are to be retrieved sequentially only, Linked List is preferred.
2. Insertion - If new Elements are to be inserted in between other elements , Linked List is preferred.
3. Search - Binary Search and other optimized way of searching is not possible on Linked List.
4. Sorting - Initial sorting could be pain but lateral addition of elements in a sorted list is good with linked list.
5. Adding Elements - If sufficiently large elements needs to be added very frequently ,Linked List is preferable as elements don't need consecutive memory location.
Ans. Keep it as a Abstract Class if its a "Is a" Relationsship and should do subset/all of the functionality. Keep it as Interface if its a "Should Do" relationship.
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Ans. Cloneable is a declaration that the class implementing it allows cloning or bitwise copy of it's object state. It is not having any method because it is a MARKER interface.
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Ans. Executor - Simple Interface that supports launching new tasks.
ExecutorService - Subinterface of Executor, which adds features that help manage the lifecycle, both of the individual tasks and of the Executor itself.
ScheduledExecutorService - Subinterface of ExecutorService, supports future and-or periodic execution of tasks.
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Ans. It doesn't matter how you define that method in implementing class. there will be only one definition provided and that method can be accessed using reference of either of the interfaces.
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3152 questions in repository.
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 )
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Which of the following statement is not true ?
