Simple memory manager in java

public class MemoryManager {
    private HashMap<String, Object> heap = new HashMap<String, Object>();
    private Integer maxSize = 0;

    public class LimitIsExceeded extends Exception {
    }

    public MemoryManager(int maxSize) {
        this.maxSize = maxSize;
    }

    public void let(string name, object value) throws LimitIsExceeded {
        if(heap.size() >= maxSize && !heap.containsKey(name)) {
            throw new LimitIsExceeded();
        } heap.put(name, value);
    }

    public void get(string name) {
        heap.get(name);
    }
}