JAVA PROGRAM • LEVEL 18 — PLACEMENT PROGRAMS & MINI PROJECTS
Build an LRU Cache in Java
Learn build an lru cache in java with a complete, compiler-ready Java 17 example.
PROBLEM UNDERSTANDING
Input and expected output
No input required
{1=A, 3=C}COMPLETE JAVA 17 PROGRAM
Complete Java 17 implementation
import java.util.*;class LruCache<K,V> extends LinkedHashMap<K,V>{private final int capacity;LruCache(int capacity){super(capacity,0.75f,true);this.capacity=capacity;}protected boolean removeEldestEntry(Map.Entry<K,V> eldest){return size()>capacity;}}class Main{public static void main(String[] args){LruCache<Integer,String> cache=new LruCache<>(2);cache.put(1,"A");cache.put(2,"B");cache.get(1);cache.put(3,"C");System.out.println(cache);}}CURRENT STEP
Select Start to walk through the important lines.
SELECTED LINE
No line selected
EXPECTED OUTPUT FOR THE SAMPLE
{1=A, 3=C}PROGRAM EXPLANATION
Algorithm and explanation
- Initialize the deterministic sample values used for build an lru cache in java.
- Create the required object and apply LinkedHashMap and LRU eviction to its state or behavior.
- Print the final result and compare it with the documented sample output.
This Java 17 example demonstrates LinkedHashMap and LRU eviction through a complete, executable program. The values are intentionally small so students can trace each statement, verify the output, and then modify the example safely in the online compiler.
EFFICIENCY
Time and space complexity
O(1) average
O(k)
DEBUGGING CHECKLIST
Common mistakes
Keep the class name Main and the entry method signature public static void main(String[] args) when using the online compiler.
Create an object before accessing instance members; static members can be accessed through the class name.
Java is case-sensitive, and every statement that requires a semicolon must end with one.