failing annotations groovy

package com.example.helloworld;

import javax.ws.rs.*;
import javax.ws.rs.core.MediaType;

@Produces(MediaType.APPLICATION_JSON)
public class HelloWorldService{  

}

// ---- Build.gradle ----

apply plugin: 'groovy'

// Set our project variables
project.ext {
    dropwizardVersion = '0.6.1'
}

repositories {
    mavenCentral()
}

dependencies {
    compile group: 'com.yammer.dropwizard', name: 'dropwizard-core', version: dropwizardVersion
    groovy group: 'org.codehaus.groovy', name: 'groovy-all', version: '1.8.7'
}

task wrapper(type: Wrapper) {
    gradleVersion = '1.3'
}