LRU cache in Java with Generics and O(1) operations

Question

This is a question that comes up a lot in job interviews. The idea is to define a data structure instead of using Java\'s built in LinkedHashMap.

An LRU cache delete

Answer 1

public class LeastRecentlyUsed {

    public static  Map leastRecentlyUsedCache(final int maxSize) {
        return new LinkedHashMap(maxSize , 0.7f, true) {
            private static final long serialVersionUID = -3588047435434569014L;
            @Override
            protected boolean removeEldestEntry(Map.Entry eldest) {
                return size() > maxSize;
            }
        };
    }

    public static void main(String[] args) {
        Map leastRecentlyUsed = LeastRecentlyUsed.leastRecentlyUsedCache(3);
        leastRecentlyUsed.put("Robert", "Raj");
        leastRecentlyUsed.put("Auzi", "Aiz");
        leastRecentlyUsed.put("Sandy", "S");
        leastRecentlyUsed.put("Tript", "tty");  
        System.out.println(leastRecentlyUsed);
    }
  }