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)
environment['AWS_LAMBDA_FUNCTION_NAME'] = context.function_name
            environment['AWS_LAMBDA_FUNCTION_VERSION'] = context.function_version
            environment['AWS_LAMBDA_FUNCTION_INVOKED_ARN'] = context.invoked_function_arn
        
        command = ''
        
        if runtime == LAMBDA_RUNTIME_JAVA8:
            java_opts = Util.get_java_opts()
            stdin = None
            
            target_file = os.path.join(lambda_cwd, os.path.basename(LAMBDA_EXECUTOR_JAR))
            if not os.path.exists(target_file):
                cp_r(LAMBDA_EXECUTOR_JAR, target_file)
            
            taskdir = '/var/task'
            save_file(os.path.join(lambda_cwd, LAMBDA_EVENT_FILE), event_body)
            classpath = Util.get_java_classpath(target_file)
            command = ("bash -c 'cd %s; java %s -cp \"%s\" \"%s\" \"%s\" \"%s\"'" %
                (taskdir, java_opts, classpath, LAMBDA_EXECUTOR_CLASS, handler, LAMBDA_EVENT_FILE))
        
        cmd = self.prepare_execution(func_arn, environment, runtime, command, handler, lambda_cwd)
        
        LOG.info('Running lambda cmd: %s' % cmd)
        result, log_output = self.run_lambda_executor(cmd, stdin, environment)
        log_formatted = log_output.strip().replace('\n', '\n> ')
        LOG.debug('Lambda %s result / log output:\n%s\n>%s' % (func_arn, result.strip(), log_formatted))
        return result, log_output
class LambdaExecutorReuseContainers(LambdaExecutorContainers):
    """ Executor class for executing Lambda functions in re-usable Docker containers """
    def __init__(self):