Example for refreshable Groovy Scripts via Java Config. RefreshableGroovyScript is a FactoryBean that produces Proxies backed by a RefreshableTargetSource. Changes in the groovy script are picked up after the configured time interval.

App.java

package demo;

import static java.util.concurrent.TimeUnit.*;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;

@SpringBootApplication
public class App {

	public static void main(String[] args) throws Exception {

		Evaluator evaluator = SpringApplication.run(App.class, args).getBean(Evaluator.class);

		for (int i = 0; i < 20; i++) {

			System.out.printf("evaluated to %s%n", evaluator.evaluate(null));

			SECONDS.sleep(1);
		}
	}

	@Bean
	public RefreshableGroovyScript evaluator() {
		return new RefreshableGroovyScript("classpath:GroovyEvaluator.groovy", Evaluator.class).refreshEvery(1, SECONDS);
	}
}

Evaluator.java

package demo;

public interface Evaluator {

	boolean evaluate(Object arg);
}

GroovyEvaluator.groovy

class GroovyEvaluator implements demo.Evaluator{

	def boolean evaluate(arg) {
		return true;
	}
}

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>

	<groupId>demo</groupId>
	<artifactId>spring-boot-groovy-reloading-demo</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<packaging>jar</packaging>

	<name>spring-boot-groovy-reloading-demo</name>
	<description>Demo project for Groovy reloading Spring Boot</description>

	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>1.3.0.M5</version>
		<relativePath /> <!-- lookup parent from repository -->
	</parent>

	<properties>
		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
		<java.version>1.8</java.version>
	</properties>

	<dependencies>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-aop</artifactId>
		</dependency>
	
		<dependency>
			<groupId>org.codehaus.groovy</groupId>
			<artifactId>groovy</artifactId>
		</dependency>

		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
			<scope>test</scope>
		</dependency>
	</dependencies>

	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
			</plugin>
		</plugins>
	</build>

	<repositories>
		<repository>
			<id>spring-snapshots</id>
			<name>Spring Snapshots</name>
			<url>https://repo.spring.io/snapshot</url>
			<snapshots>
				<enabled>true</enabled>
			</snapshots>
		</repository>
		<repository>
			<id>spring-milestones</id>
			<name>Spring Milestones</name>
			<url>https://repo.spring.io/milestone</url>
			<snapshots>
				<enabled>false</enabled>
			</snapshots>
		</repository>
	</repositories>
	<pluginRepositories>
		<pluginRepository>
			<id>spring-snapshots</id>
			<name>Spring Snapshots</name>
			<url>https://repo.spring.io/snapshot</url>
			<snapshots>
				<enabled>true</enabled>
			</snapshots>
		</pluginRepository>
		<pluginRepository>
			<id>spring-milestones</id>
			<name>Spring Milestones</name>
			<url>https://repo.spring.io/milestone</url>
			<snapshots>
				<enabled>false</enabled>
			</snapshots>
		</pluginRepository>
	</pluginRepositories>

</project>

RefreshableGroovyScript.java

package demo;

import java.time.Duration;
import java.time.temporal.ChronoUnit;
import java.util.concurrent.TimeUnit;

import org.springframework.aop.TargetSource;
import org.springframework.aop.framework.ProxyFactory;
import org.springframework.aop.support.DelegatingIntroductionInterceptor;
import org.springframework.beans.factory.FactoryBean;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.core.io.DefaultResourceLoader;
import org.springframework.core.io.FileSystemResource;
import org.springframework.core.io.Resource;
import org.springframework.scripting.ScriptFactory;
import org.springframework.scripting.ScriptSource;
import org.springframework.scripting.groovy.GroovyScriptFactory;
import org.springframework.scripting.support.ResourceScriptSource;

class RefreshableGroovyScript implements FactoryBean<Object>, InitializingBean {

	private Object delegate;

	private Duration refreshInterval = Duration.ZERO;
	private String scriptLocation;
	private Class<?> type;

	public RefreshableGroovyScript(String scriptLocation, Class<?> type) {
		this.scriptLocation = scriptLocation;
		this.type = type;
	}

	@Override
	public Object getObject() {
		return delegate;
	}

	@Override
	public Class<?> getObjectType() {
		return type;
	}

	@Override
	public boolean isSingleton() {
		return true;
	}

	public Duration getRefreshInterval() {
		return refreshInterval;
	}

	public void setRefreshInterval(Duration refreshInterval) {
		this.refreshInterval = refreshInterval;
	} 

	public RefreshableGroovyScript withRefreshEvery(Duration duration) {
		setRefreshInterval(duration);
		return this;
	}

	public RefreshableGroovyScript refreshEvery(int amount, TimeUnit timeUnit) {

		setRefreshInterval(Duration.of(amount, ChronoUnit.valueOf(timeUnit.name())));
		return this;
	}

	@Override
	public void afterPropertiesSet() throws Exception {
		this.delegate = createPotentiallyRefreshableDelegate(createRefreshableTargetSource());
	}

	private Object createPotentiallyRefreshableDelegate(SimpleRefreshableScriptTargetSource srsts) {
		return refreshInterval == Duration.ZERO ? srsts.freshTarget() : createRefreshableProxy(srsts);
	}

	private SimpleRefreshableScriptTargetSource createRefreshableTargetSource() {

		Resource resource = new DefaultResourceLoader().getResource(scriptLocation);
		ScriptFactory factory = new GroovyScriptFactory(resource instanceof FileSystemResource ? "file" : "classpath");
		ScriptSource script = new ResourceScriptSource(resource);

		SimpleRefreshableScriptTargetSource srsts = new SimpleRefreshableScriptTargetSource(script, factory);
		srsts.setRefreshCheckDelay(refreshInterval.toMillis());
		return srsts;
	}

	private Object createRefreshableProxy(SimpleRefreshableScriptTargetSource srsts) {

		ProxyFactory proxyFactory = new ProxyFactory();
		proxyFactory.setTargetSource(srsts);
		proxyFactory.setInterfaces(type);

		DelegatingIntroductionInterceptor introduction = new DelegatingIntroductionInterceptor(srsts);
		introduction.suppressInterface(TargetSource.class);
		proxyFactory.addAdvice(introduction);

		return proxyFactory.getProxy();
	}
}

SimpleRefreshableScriptTargetSource.java

package demo;

import java.io.IOException;

import org.springframework.aop.target.dynamic.AbstractRefreshableTargetSource;
import org.springframework.scripting.ScriptCompilationException;
import org.springframework.scripting.ScriptFactory;
import org.springframework.scripting.ScriptSource;

class SimpleRefreshableScriptTargetSource extends AbstractRefreshableTargetSource {

	private final ScriptSource script;
	private final ScriptFactory factory;

	public SimpleRefreshableScriptTargetSource(ScriptSource script, ScriptFactory factory) {
		this.script = script;
		this.factory = factory;
	}

	@Override
	protected Object freshTarget() {
		try {
			return factory.getScriptedObject(script);
		} catch (ScriptCompilationException | IOException e) {
			throw new RuntimeException(e);
		}
	}
}

Would be nice to have a complete maven directory structure - at least in the download zip.