Create REST API

First of all, try to consider to use OOB REST functionality. It's pretty wide to cover different business needs: especially through server-side scripting (OFunction). But if you need to have your own REST API in any case: to add it is extremly easy.

Add the following snippets into pom.xml of your project.

To root project xml element:

<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>org.glassfish.jersey</groupId>
            <artifactId>jersey-bom</artifactId>
            <version>2.23.1</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
    </dependencies>
</dependencyManagement>

To a list of projects:

<dependency>
    <groupId>org.glassfish.jersey.containers</groupId>
    <artifactId>jersey-container-servlet</artifactId>
</dependency>

<dependency>
    <groupId>org.glassfish.jersey.test-framework.providers</groupId>
    <artifactId>jersey-test-framework-provider-bundle</artifactId>
    <type>pom</type>
    <scope>test</scope>
</dependency>

Also make sure that you use Servlet 3.0+ compatible web container.