collection interface methods in java

Methods of Collection

1. What are the methods in collection interface?
2. What are the different types of collections in Java?
3. What are the basic interfaces of Java Collections Framework?
4. How many interfaces are in a collection?
5. What are collection Apis give me an example?
6. Is HashSet an interface?
7. Why Collection is a framework?
8. What is difference between Array and ArrayList?
9. What is difference between collection and collections in Java?
10. Is array a collection in Java?
11. Is map a collection in Java?
12. Why we go for collections in Java?

What are the methods in collection interface?

The Collection interface contains methods that perform basic operations, such as int size() , boolean isEmpty() , boolean contains(Object element) , boolean add(E element) , boolean remove(Object element) , and Iterator<E> iterator() .

What are the different types of collections in Java?

Collections in Java

• HashSet Class.
• TreeSet Class.
• ArrayList Class.
• LinkedList Class.
• HashMap Class.
• TreeMap Class.
• PriorityQueue Class.

What are the basic interfaces of Java Collections Framework?

Java Collection framework provides many interfaces (Set, List, Queue, Deque) and classes (ArrayList, Vector, LinkedList, PriorityQueue, HashSet, LinkedHashSet, TreeSet).

How many interfaces are in a collection?

The collection hierarchy consists of six interfaces, the core collection intefaces. Three of these interfaces, Set, List, and SortedSet are descendants of the Collection interface; they add further constraints on the contracts imposed by the methods in this interface, as well as adding new methods.

What are collection Apis give me an example?

The Collection API is a set of classes and interfaces that support operation on collections of objects. Example of classes: HashSet, HashMap, ArrayList, LinkedList, TreeSet and TreeMap. ... Example of interfaces: Collection, Set, List and Map.

Is HashSet an interface?

The HashSet class implements the Set interface, backed by a hash table which is actually a HashMap instance. No guarantee is made as to the iteration order of the set which means that the class does not guarantee the constant order of elements over time. This class permits the null element.

Why Collection is a framework?

Any group of individual objects which are represented as a single unit is known as the collection of the objects. In Java, a separate framework named the “Collection Framework” has been defined in JDK 1.2 which holds all the collection classes and interface in it. The Collection interface (java.

What is difference between Array and ArrayList?

Array is a fixed size data structure while ArrayList is not. One need not to mention the size of Arraylist while creating its object. Even if we specify some initial capacity, we can add more elements. Array can contain both primitive data types as well as objects of a class depending on the definition of the array.

What is difference between collection and collections in Java?

The Collection is an interface whereas Collections is a utility class in Java. The Set, List, and Queue are some of the subinterfaces of Collection interface, a Map interface is also part of the Collections Framework, but it doesn't inherit Collection interface.

Is array a collection in Java?

In order to store multiple values or objects of the same type, Java provides two types of data structures namely Array and Collection. ... Arrays can hold the only the same type of data in its collection i.e only homogeneous data types elements are allowed in case of arrays.

Is map a collection in Java?

Because a Map is not a true collection, its characteristics and behaviors are different than the other collections like List or Set. A Map cannot contain duplicate keys and each key can map to at most one value.

Why we go for collections in Java?

The Java collections framework gives the programmer access to prepackaged data structures as well as to algorithms for manipulating them. A collection is an object that can hold references to other objects. The collection interfaces declare the operations that can be performed on each type of collection.