What is a collection in Java?

A collection is a container that holds a group of objects. The collection provides a way to manage objects easily. Collections manage groups of objects as a single unit.

Read also: What is Vector Java?

Common Collection Types

1. List:
   • ArrayList: Best for general-purpose storage and fast random access.
   • LinkedList: Good for frequent insertions and deletions.
2. Set:
   • HashSet: Use when you need a set with no duplicates and order doesn’t matter.
   • LinkedHashSet: Maintains insertion order.
   • TreeSet: Keeps elements sorted.
3. Map:
   • HashMap: Best for general-purpose key-value storage.
   • LinkedHashMap: Maintains insertion order.
   • TreeMap: Stores keys in sorted order.

Here are a few basic operations we do on collections :
1) Adding objects to the collection.
2) Removing or deleting objects from the collection.
3) Retrieving objects from the collection.
4) Iterating collection

Understanding the Java Collections Framework

When you and I work with Java, we often need to handle groups of objects—like lists, sets, or maps. That’s where the Collections Framework comes in. Think of it as a well-organized system that helps us store, access, and manage collections of data efficiently.

Java’s Collections Framework is part of the java.util package and was introduced in JDK 1.2. It’s still one of the most widely used tools in Java development today. It gives us a structured hierarchy of interfaces and classes, making it easier to manage data structures like lists, queues, sets, and more—without writing everything from scratch.

Before this framework existed, we had tools like Arrays, Stacks, and Vectors. While they were useful, they weren’t connected under a common structure. As a result, you had to learn different methods for each one, and they didn’t offer much flexibility or performance.

With the Collections Framework, we now have a consistent and unified approach. It saves you time and effort by offering ready-to-use classes and interfaces, along with built-in algorithms. So whether you’re sorting a list or searching a set, the Collections Framework makes it simpler and more efficient.