code: public V put( final K key, final V value ) {
          synchronized ( _map ) {
              final ManagedItem<V> previous = _map.put( key, new ManagedItem<V>( value, System.currentTimeMillis() ) );
              while ( _map.size() > _size ) {
                  _map.remove( _map.keySet().iterator().next() );
              }
              return previous != null
                  ? previous._value
                  : null;
          }
      }
docs: Put the key and value.
  
  @param key
  the key
  @param value
  the value
  @return the previously associated value or <code>null</code>.