The lambda execution is not suspending and the lambda container has no port exposed when running a java 11 lambda with the latest localstack docker image by docker-compose with the environment variable LAMBDA_JAVA_OPTS=-agentlib:jdwp=transport=dt_socket,server=y,suspend=y,address=_debug_port_
    
It works fine for java8 runtime executions.

Docker command:

> localstack_1  | 2020-01-26T12:42:04:INFO:localstack.services.awslambda.lambda_executors: Running lambda cmd: CONTAINER_ID="$(docker create -i   -e ENV="$ENV" -e DOCKER_LAMBDA_USE_STDIN="$DOCKER_LAMBDA_USE_STDIN" -e HOSTNAME="$HOSTNAME" -e LOCALSTACK_HOSTNAME="$LOCALSTACK_HOSTNAME" -e AWS_LAMBDA_FUNCTION_TIMEOUT="$AWS_LAMBDA_FUNCTION_TIMEOUT" -e AWS_LAMBDA_FUNCTION_NAME="$AWS_LAMBDA_FUNCTION_NAME" -e AWS_LAMBDA_FUNCTION_VERSION="$AWS_LAMBDA_FUNCTION_VERSION" -e AWS_LAMBDA_FUNCTION_INVOKED_ARN="$AWS_LAMBDA_FUNCTION_INVOKED_ARN"  --rm "lambci/lambda:java11" "com.XXX.XXX.Handler")";docker cp "/tmp/localstack/zipfile.0c90736c/." "$CONTAINER_ID:/var/task"; docker start -ai "$CONTAINER_ID";

I think this is due to the fact that the classpath arguments and java opts are only being set if the rutime is equal to LAMBDA_RUNTIME_JAVA8 (line 211 of ocalstack/localstack/services/awslambda/lambda_executors.py , commit 03c6f4bf250edd18eb818ed65090f508636b0bff)
return ''
            
            container_name = self.get_container_name(func_arn)
            docker_cmd = self._docker_cmd()
            
            LOG.debug('Getting container network: %s' % container_name)
            cmd = (
                '%s inspect %s'
                ' --format "{{ .HostConfig.NetworkMode }}"'
            ) % (docker_cmd, container_name)
            LOG.debug(cmd)
            cmd_result = run(cmd, asynchronous=False, stderr=subprocess.PIPE, outfile=subprocess.PIPE)
            container_network = cmd_result.strip()
            return container_network
    def idle_container_destroyer(self):
        """
        Iterates though all the lambda containers and destroys any container that has
        been inactive for longer than MAX_CONTAINER_IDLE_TIME_MS.
        :return: None
        """
        LOG.info('Checking if there are idle containers.')
        current_time = int(time.time() * 1000)
        for func_arn, last_run_time in dict(self.function_invoke_times).items():
            duration = current_time - last_run_time
            
            if duration < MAX_CONTAINER_IDLE_TIME_MS:
                continue
            
            self.destroy_docker_container(func_arn)
    def start_idle_container_destroyer_interval(self):