Question

1. Is List type is an interface in the Java collections framework?
2. Classes Vector, ArrayList, and LinkedList are the same data structure but implement data storage in different ways.
3. Classes, that implement Map interface in Java collections framework are used for storing what type of data?
4. Declare and instantiate a list of elements of type String. Name this list myArray.
5. what type of data structure is Stack?
6. LinkedList data structure in Java collections is implemented as doubly linked lists.
7. In PriorityQueue data structure how are the elements placed at the front of the queue?
8. What type of data structure is a set?

Answer 1

Ans1

• Yes List type is an interface in java Collection Framework
• List is a child iterface of collection
• if we want to represent a group of individual object as a sing entity where duplicte are allowed and inserrtion order must be preserve the we go for List interface

Ans 2:

• MAp is not a child interface of collection
• If we want ot repreent a group of object as key value pairs then we should go for map interface
• Duplicate keys are not allowed but we can store duplicate values.
• the child iterface of map consist of Hashmap,IdentityHashmap,SotedMap.

Ans 3:

Declare and instantiate a list of elements of type String

we can declare list using mainly 3 classes because this 3 classes has implemented list interface.This 3 classes are ArrayList,LinkedList,Stack.There are other classes also which implemented List interface.

Hence lets initialise List interface using this 3 classes

Example:

1. List<String> myArray=new ArrayList<String>();

2. List<String> myArray=new LinkedList<String>();
   

3. List<String> myArray=new Stack<String>();
   

what type of data structure is Stack?

ans: Stack is a Linear Data Structure in which order of data can be LIFO(Last In First Out) or FILO(First In Last Out)

Ans 4:

• Yes Likedlist in java collection framework has doubly Linkedlist data structure implemented
• If our frequent operation is insertion and deletion then linkedlist is best choice

Ans 5:

• we can use priority quee to represent a group of individual object prior to processing according to some priority
• the priority order can be either default natural sorting order or customized sorting order
• if we are depending on default sorting order then object must be homogeneouus(same) or compaable otherwise we will get classcatexception
• Duplicate objects are not allowed
• Null is not allowed in priorty Queue

Ans 6:

Set is an abstract data type that can store unique values, without any particular order.

Thank You!