Cached PreparedStatements in connection pools. Will this work out?

CachedConnection.java

public class CachedConnection implements Connection
{
    // Yay for delegation :3
    // Just for the non Lombok people, it will automatically
    // create methods that delegate functionality to this object
    @Delegate(types = Connection.class)
    private final Connection connection;
    
    private final Map<String, PreparedStatement> cachedStatements;
    
    public CachedConnection(Connection connection)
    {
        this.connection = connection;
        this.cachedStatements = new MapMaker().weakValues().<String, PreparedStatement>make();
    }
    
    public void query(String query, Object[] args)
    {
        PreparedStatement stmt = getOrPrepare(query);
        // do rest
    }
    
    private PreparedStatement getOrPrepare(String query)
    {
        PreparedStatement stmt = this.cachedStatements.get(query);
        if(stmt == null)
        {
            stmt = this.connection.prepareStatement(query);
            this.cachedStatements.put(query, stmt);
        }
        return stmt;
    }
    
    protected void cleanup()
    {
        this.connection = null;
        this.cachedStatements.clear();
        this.cachedStatements = null;
    }
    
}

ConnectionPool.java

public interface ConnectionPool
{

    /**
     * Returns a Connection if:
     * - There is a valid idle connection.
     * - The sum of connections is less than the max limit
     *   and it is able to create one.
     * @return a {@link CachedConnection} from the ConnectionPool
     */
    public CachedConnection lease();
    
    /**
     * Used to return a connection to the ConnectionPool,
     * marking it as idle. Will call CachedConnection#cleanup().
     */
    public void returnConnection(CachedConnection con);
    
}