What is polymorphism?

Correct Answer: A JAR file (short for Java Archive) is a ZIP file used to distribute a set of Java classes It is used to store compiled Java classes and associated metadata that can constitute a program

Correct Answer: B+ tree structure

Explanation:

B+ tree. Because in B+ tree, all the data is stored only in leaf nodes, that makes searching easier. This corresponds to the records that shall be stored in leaf nodes

Correct Answer: Overloading allows multiple functions to exist with same name but different parameters Again if you take bike as an example, it has a function “Start” with two forms ie ?Auto Start? and ?kick start?

Correct Answer: The heterogeneous linked list contains different data types in its nodes and we need a link, pointer to connect them It is not possible to use ordinary pointers for this So we go for void pointer Void pointer is capable of storing pointer to any type as it is a generic pointer type

Correct Answer: Two types of classes: 1) Top Level Class 2) Classes within Class i) member classes a) static member class b) non static member class ii) local classes iii) anonymous classes

Correct Answer: :: is the scope resolution operator When local variable and global variable are having same name, local variable gets the priority C++ allows flexibility of accessing both the variables through a scope resolution operator

Correct Answer: Overriding means changing behavior of methods of base class in derive class by overriding the base class methods If class A is a base class with method ?calculate? and class B inherits class A, thus derives method ?calculate? of class A The behavior of ?calculate? in class B can be changed by overriding it

Correct Answer: Use Interfaces when? - You see that something in your design will change frequently - If various implementations only share method signatures then it is better to use Interfaces - You need some classes to use some methods which you don't want to be included in the class, then you go for the interface, which makes it easy to just implement and make use of the methods defined in the interface Use Abstract Class when? - If various implementations are of the same kind and use common behavior or status then abstract class is better to use - When you want to provide a generalized form of abstraction and leave the implementation task with the inheriting subclass - Abstract classes are an excellent way to create planned inheritance hierarchies They're also a good choice for nonleaf classes in class hierarchies

Correct Answer: To use an iterator to traverse through the contents of a collection, follow these steps: - Obtain an iterator to the start of the collection by calling the collections iterator() method - Set up a loop that makes a call to hasNext() Have the loop iterate as long as hasNext() returns true - Within the loop, obtain each element by calling next()

Correct Answer: If you need to support random access, without inserting or removing elements from any place other than the end, then ArrayList offers the optimal collection If, however, you need to frequently add and remove elements from the middle of the list and only access the list elements sequentially, then LinkedList offers the better implementation