LRU Cache System (Java)

Overview

This project implements a Least Recently Used (LRU) Cache in Java. The cache supports constant time get and put operations while maintaining a fixed capacity.

Problem Statement

In systems with limited memory, frequently accessed data should be retrieved quickly. An LRU Cache removes the least recently used item when the cache reaches its capacity.

Approach

• HashMap is used for O(1) access to cache entries
• Doubly Linked List is used to maintain usage order
• Most recently used items are moved to the front
• Least recently used items are evicted when capacity is exceeded

Features

• O(1) get and put operations
• LRU eviction policy
• Cache hit and miss tracking

How to Run

javac LRUCache.java Main.java
java Main

Sample Output

10
-1
-1
30
40
Cache Hits: 3
Cache Misses: 2

Learning Outcome

This project helped me understand how multiple data structures can be combined to solve real-world performance problems efficiently.