Java data structures

Category : Java | Sub Category : Java Interview questions | By Prasad Bonam Last updated: 2023-07-10 03:15:51 Viewed : 333

Java data structures:

Java provides a rich set of built-in data structures that can be used to store and manipulate data efficiently. Here are some commonly used data structures in Java:

1. Arrays: Arrays are fixed-size data structures that store elements of the same type in contiguous memory locations. They provide fast random access but have a fixed size and cannot be dynamically resized.

2. ArrayList: ArrayList is a dynamic array implementation that can grow or shrink dynamically. It provides methods for adding, removing, and accessing elements efficiently. ArrayList is part of the Java Collections Framework.

3. LinkedList: LinkedList is a data structure in which elements are stored in nodes that contain a reference to the next node. It supports fast insertion and deletion operations but provides slower random access compared to ArrayList.

4. Stack: Stack is a Last-In-First-Out (LIFO) data structure that supports two main operations: push (adds an element to the top of the stack) and pop (removes the top element from the stack). Java provides the Stack class for stack implementation.

5. Queue: Queue is a First-In-First-Out (FIFO) data structure that supports two main operations: enqueue (adds an element to the end of the queue) and dequeue (removes the element from the front of the queue). Java provides the Queue interface and several implementations like LinkedList and PriorityQueue.

6. HashSet: HashSet is an implementation of the Set interface that stores unique elements. It does not maintain the insertion order of elements but provides constant-time performance for basic operations like add, remove, and contains.

7. TreeSet: TreeSet is an implementation of the SortedSet interface that stores elements in sorted order. It provides efficient operations for adding, removing, and accessing elements in sorted order.

8. HashMap: HashMap is an implementation of the Map interface that stores key-value pairs. It provides fast access and retrieval of values based on keys. HashMap allows null keys and values but does not guarantee the order of elements.

9. TreeMap: TreeMap is an implementation of the SortedMap interface that stores key-value pairs in sorted order based on the keys. It provides efficient operations for adding, removing, and accessing elements in sorted order.

10. PriorityQueue: PriorityQueue is an implementation of the Queue interface that stores elements based on their priority. Elements with higher priority are dequeued first. It can be used to implement a priority queue or to sort elements based on a specific ordering.

These are just a few examples of the built-in data structures available in Java. The Java Collections Framework provides a comprehensive set of interfaces and classes that cater to different data manipulation requirements. Depending on your specific use case, you can choose the appropriate data structure to optimize performance and achieve the desired functionality.