Set Interface.

Question 1

1. Does set contains insertion order and duplicate?
2. What are all the Set interface?
3. wt is the ds of set I ?
4. If you want sorting in Set what will you do?
5. Wt are the sub Interface we have in Set?
6. Does linkedhash set follow insertion order?

Answer 1

1. Duplicates not allowed and insertion order also not allowed.
2. Hashset and Linked hashset
3. Linked List is the DS
4. I can use Sorted set (sub interface). for this
5. We have Sorted set , navigable set , tree set .

Question 2

1. How to convert linkedlist to linked hashset?
2. Very Important , how do you convert a collection into Array?
3. Very Important. if we convert toarray() incase if we have string value to in linked list what will happen ?
4. What happen if we give

ll.add(sd);
Here, sd is a object name.

Answer 2

1. Create linkedhashset object and pass the reference name in the print (parameters).
2. By giving toarray();, but map can’t change
3. It won’t print to make it print all obejcts we need to give
   Object ob = ll.toarray().
   Note: Because, why we giving object because Array accepts only homogenous objects .

and object is parent of all the String [] , char[] , int[] , and we can create our own array too like Laptop [] .
4. sd is a object name so it will print output as hashcode
To print a string , we need to give public void toString() method and give return “ABC”; Now it will print ABCas output.

Question 3

1. What is the use of toString() method?

Answer 3

1.The toString method is used to return a string representation of an object. If any object is printed, the toString() method is internally invoked by the java compiler.

Question 4

Tree Set