#vulnerable code 
                                @Test
    public void testConnectTriesToReconnectOnFailedConnectAttempt(final TestContext ctx) {

        // GIVEN a client that cannot connect to the server
        ProtonConnection con = mock(ProtonConnection.class);
        // expect the connection factory to fail twice and succeed on third connect attempt
        DisconnectHandlerProvidingConnectionFactory connectionFactory = new DisconnectHandlerProvidingConnectionFactory(con, 1, 2);
        HonoClientImpl client = new HonoClientImpl(vertx, connectionFactory);

        // WHEN trying to connect
        Async disconnectHandlerInvocation = ctx.async();
        Async connectionEstablished = ctx.async();
        Handler<ProtonConnection> disconnectHandler = failedCon -> disconnectHandlerInvocation.complete();
        client.connect(
                new ProtonClientOptions().setReconnectAttempts(1),
                ctx.asyncAssertSuccess(ok -> connectionEstablished.complete()),
                disconnectHandler);

        // THEN the client repeatedly tries to connect
        connectionEstablished.await(4 * Constants.DEFAULT_RECONNECT_INTERVAL_MILLIS);
        // and sets the disconnect handler provided as a param in the connect method invocation
        connectionFactory.getDisconnectHandler().handle(con);
        disconnectHandlerInvocation.await(1000);
    } 
                            #location 22 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                                @Test
    public void testConnectTriesToReconnectOnFailedConnectAttempt(final TestContext ctx) {

        // GIVEN a client that cannot connect to the server
        // expect the connection factory to fail twice and succeed on third connect attempt
        connectionFactory = new DisconnectHandlerProvidingConnectionFactory(con, 1, 2);
        final HonoClientImpl client = new HonoClientImpl(vertx, connectionFactory);

        // WHEN trying to connect
        Async disconnectHandlerInvocation = ctx.async();
        Async connectionEstablished = ctx.async();
        client.connect(
                new ProtonClientOptions().setReconnectAttempts(1),
                ctx.asyncAssertSuccess(ok -> connectionEstablished.complete()),
                failedCon -> disconnectHandlerInvocation.complete());

        // THEN the client repeatedly tries to connect
        connectionEstablished.await(4 * Constants.DEFAULT_RECONNECT_INTERVAL_MILLIS);
        // and sets the disconnect handler provided as a param in the connect method invocation
        connectionFactory.getDisconnectHandler().handle(con);
        disconnectHandlerInvocation.await();
    }