public boolean hasSetupWorkspace() {
        Object result = commandService.executeClientCommand(
                new ExecuteCommandParams("vespaSchemaLS.commands.schema.hasSetupWorkspace", List.of())).join();
        if (result == null) return false;
        try {
            String json = gson.toJson(result);
            Type booleanType = new TypeToken<Boolean>() {}.getType();
            return gson.fromJson(json, booleanType);
        } catch (Exception ex) {
            logger.severe("Error when parsing json: " + ex.getMessage());
        }

        return false;
    }
Singleton to interface the Schema Language server through the client.
integration/schema-language-server/lemminx-vespa/src/main/java/ai/vespa/lemminx/command/SchemaLSCommands.java