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)
""" Create new event source mapping
        ---
        operationId: 'createEventSourceMapping'
        parameters:
            - name: 'request'
              in: body
    """
    data = json.loads(to_str(request.data))
    mapping = add_event_source(data['FunctionName'], data['EventSourceArn'], data.get('Enabled'))
    return jsonify(mapping)
@app.route('%s/event-source-mappings/<mapping_uuid>' % PATH_ROOT, methods=['PUT'])
def update_event_source_mapping(mapping_uuid):
    """ Update an existing event source mapping
        ---
        operationId: 'updateEventSourceMapping'
        parameters:
            - name: 'request'
              in: body
    """
    data = json.loads(request.data)
    if not mapping_uuid:
        return jsonify({})
    function_name = data.get('FunctionName') or ''
    enabled = data.get('Enabled', True)
    batch_size = data.get('BatchSize') or 100
    mapping = update_event_source(mapping_uuid, function_name, enabled, batch_size)
    return jsonify(mapping)
@app.route('%s/event-source-mappings/<mapping_uuid>' % PATH_ROOT, methods=['DELETE'])
def delete_event_source_mapping(mapping_uuid):