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In this tutorial we will learn what is java.util.Collection in java.

1. What is java.util.Collection?

java.util.Collection is the root interface in the hierarchy of Java Collection framework.

The JDK does not provide any classes which directly implements this interface, but it provides classes which are implementations of more specific subinterfaces like Set and List in java.

2. Set and List extends Collection

java.util.Set extends java.util.Collection interface in java.

HashSet, CopyOnWriteArraySet, LinkedHashSet, TreeSet, ConcurrentSkipListSet, EnumSet classes implements Set interface.

java.util.List extends java.util.Collection interface in java.

ArrayList, LinkedList, Vector, CopyOnWriteArrayList classes implements List interface.

Generally speaking a collection represents a group of objects, known as its elements.

3. Features of Collection in java >

Let's discuss feature/properties of java.util.Collection in java >

Some allow Duplicate elements.
Some maintains insertion order.
Some are Sorted by natural order.
Some are synchronized.
Some allow null elements.
Some return fail-fast iterator while others return fail-safe iterator.

4. Advantages of using Collection in java >

Advantages of using java.util.Collection in java >

Performance - JDK provides many classes which implements subInterface of Collection like java.util.List and java.util.Set interface.

Optimised and tested - Collection implementations are optimised and well tested in java.

Reusability - They can be reused in java.

No need to write code - We need not to write code for storing elements i.e. we need to write code to implement basic data structure, neither we need not to write any code to implement Set and List in java.

It’s important to note java.util.Map interface is a member of the Java Collections Framework, but it does not implement java.util.Collection interface in java.

So in this tutorial we learned what is java.util.Collection in java.