LRULinkedHashMap.java

// I really don't like inheritance, i prefer composition, but the removeEldestEntry is a protected method, have to do this
public class LRULinkedHashMap extends LinkedHashMap<Integer, Integer> {
    private int maxSize = -1;

    // This is simply use a LinkedHashMap, sort of cheating
    public LRULinkedHashMap(int capacity) {
        super(16, 0.75f, true);  // the 16 hashtable size is not to be confused with the max cache size
        this.maxSize = capacity;
    }

    public int get(int key) {
        return (int)super.getOrDefault(key, -1);
    }

    public void put(int key, int value) {
        super.put(key, value);
    }

    // as suggested in the java doc
    @Override
    public boolean removeEldestEntry(Map.Entry<Integer, Integer> eldest) {
        return super.size() > this.maxSize;
    }
}