Hot reload for Grails 4 & JDK 8

build.gradle

@@ -31,6 +31,7 @@ ext {
     groovyVersion = System.getenv('CI_GROOVY_VERSION') ?: "2.5.6"
     isBuildSnapshot = grailsVersion.endsWith(".BUILD-SNAPSHOT")
     isTravisBuild = System.getenv().get("TRAVIS") == 'true'
+    springLoadedCommonOptions = "-Xverify:none -Dspringloaded.synchronize=true -Djdk.reflect.allowGetCallerClass=true"
     dependencyVersions = [
         'javax.annotation-api': [
                 version: javaxAnnotationApiVersion,
@@ -85,6 +86,12 @@ ext {
             names  : ['directory-watcher'],
             modules: ['']
         ],
+        springLoaded: [
+            version: springLoadedVersion,
+            group  : 'org.springframework',
+            names  : ['springloaded'],
+            modules: ['']
+        ],
         async: [
             version: asyncVersion,
             group  : 'org.grails.plugins',

gradle.properties

@@ -4,6 +4,7 @@ springVersion=5.1.11.RELEASE
 spockVersion=1.2-groovy-2.5
 micronautVersion=1.1.4
 micronautSpringVersion=1.0.2
+springLoadedVersion=1.2.8.RELEASE
 gradleSdkVendorVersion=1.1.1
 jaxbVersion=2.3.1
 javaxAnnotationApiVersion=1.3.2

grails-bootstrap/src/main/groovy/grails/util/Environment.java

@@ -23,6 +23,8 @@
 import org.codehaus.groovy.runtime.DefaultGroovyMethods;
 import org.grails.io.support.Resource;
 import org.grails.io.support.UrlResource;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 import java.io.File;
 import java.io.IOException;
@@ -51,14 +53,16 @@ public enum Environment {
     TEST,
 
     /**
-     * For the application data source, primarly for backward compatability for those applications
+     * For the application data source, primarily for backward compatibility for those applications
      * that use ApplicationDataSource.groovy.
      */
     APPLICATION,
 
     /** A custom environment */
     CUSTOM;
 
+    private static final Logger LOG = LoggerFactory.getLogger(Environment.class);
+
     /**
      * Constant used to resolve the environment via System.getProperty(Environment.KEY)
      */
@@ -659,9 +663,23 @@ public static boolean isReloadingAgentEnabled() {
         try {
             Class.forName("org.springframework.boot.devtools.RemoteSpringApplication");
             reloadingAgentEnabled = Environment.getCurrent().isReloadEnabled();
+            LOG.debug("Found spring-dev-tools on the class path");
         }
         catch (ClassNotFoundException e) {
             reloadingAgentEnabled = false;
+            try {
+                String jvmVersion = System.getProperty("java.specification.version");
+                if(jvmVersion.equals("1.8")) {
+                    Class.forName("org.springsource.loaded.TypeRegistry");
+                    LOG.debug("Found spring-loaded on the class path");
+                    reloadingAgentEnabled = Environment.getCurrent().isReloadEnabled();
+                } else {
+                    LOG.warn("Found spring-loaded on classpath but JVM is not 1.8 - skipping");
+                }
+            }
+            catch (ClassNotFoundException e1) {
+                reloadingAgentEnabled = false;
+            }
         }
         return reloadingAgentEnabled;
     }

grails-bootstrap/src/main/groovy/org/grails/exceptions/reporting/DefaultStackTraceFilterer.java

@@ -47,6 +47,7 @@ public class DefaultStackTraceFilterer implements StackTraceFilterer {
         "sun.",
         "java.lang.reflect.",
         "org.springframework.boot.devtools.",
+        "org.springsource.loaded.",
         "com.opensymphony.",
         "javax.servlet."
     };

grails-core/src/main/groovy/grails/boot/GrailsApp.groovy

@@ -103,7 +103,7 @@ class GrailsApp extends SpringApplication {
         log.debug("Current base directory is [{}]. Reloading base directory is [{}]", new File("."), BuildSettings.BASE_DIR)
 
         if(environment.isReloadEnabled()) {
-            log.debug("Reloading status: ", environment.isReloadEnabled())
+            log.debug("Reloading status: {}", environment.isReloadEnabled())
             enableDevelopmentModeWatch(environment, applicationContext)
         }
         printRunStatus(applicationContext)
@@ -326,8 +326,6 @@ class GrailsApp extends SpringApplication {
             }
             directoryWatcher.start()
         }
-
-
     }
 
     static boolean isDevelopmentModeActive() {

grails-core/src/main/groovy/grails/dev/Support.groovy

@@ -47,7 +47,9 @@ class Support {
         }
 
         def environment = Environment.current
-        if(environment.isReloadEnabled() && !ClassUtils.isPresent("org.springframework.boot.devtools.RemoteSpringApplication", System.classLoader)) {
+        if(environment.isReloadEnabled() &&
+                (!ClassUtils.isPresent("org.springsource.loaded.SpringLoaded", System.classLoader) ||
+                        !ClassUtils.isPresent("org.springsource.loaded.TypeRegistry", System.classLoader))) {
             def grailsHome = System.getenv(Environment.ENV_GRAILS_HOME)
 
             if(grailsHome) {

grails-plugin-controllers/src/main/groovy/org/grails/plugins/web/controllers/ControllersGrailsPlugin.groovy

@@ -18,7 +18,6 @@ package org.grails.plugins.web.controllers
 import grails.config.Settings
 import grails.core.GrailsControllerClass
 import grails.plugins.Plugin
-import grails.util.Environment
 import grails.util.GrailsUtil
 import groovy.transform.CompileStatic
 import groovy.util.logging.Slf4j
@@ -33,7 +32,6 @@ import org.grails.web.servlet.view.CompositeViewResolver
 import org.springframework.beans.factory.support.AbstractBeanDefinition
 import org.springframework.boot.autoconfigure.web.servlet.DispatcherServletRegistrationBean
 import org.springframework.boot.web.servlet.FilterRegistrationBean
-import org.springframework.boot.web.servlet.ServletRegistrationBean
 import org.springframework.boot.web.servlet.filter.OrderedFilter
 import org.springframework.context.ApplicationContext
 import org.springframework.util.ClassUtils
@@ -57,6 +55,10 @@ import javax.servlet.MultipartConfigElement
 @Slf4j
 class ControllersGrailsPlugin extends Plugin {
 
+    def watchedResources = [
+            "file:./grails-app/controllers/**/*Controller.groovy",
+            "file:./plugins/*/grails-app/controllers/**/*Controller.groovy"]
+
     def version = GrailsUtil.getGrailsVersion()
     def observe = ['domainClass']
     def dependsOn = [core: version, i18n: version, urlMappings: version]
@@ -200,7 +202,6 @@ class ControllersGrailsPlugin extends Plugin {
             this.resourcesPattern = resourcesPattern
         }
 
-        @Override
         @Override
         public void addResourceHandlers(ResourceHandlerRegistry registry) {
             if (!addMappings) {
@@ -220,4 +221,33 @@ class ControllersGrailsPlugin extends Plugin {
         }
     }
 
+    @Override
+    void onChange( Map<String, Object> event) {
+        if (!(event.source instanceof Class)) {
+            return
+        }
+        def application = grailsApplication
+        if (application.isArtefactOfType(ControllerArtefactHandler.TYPE, (Class)event.source)) {
+            ApplicationContext context = applicationContext
+            if (!context) {
+                if (log.isDebugEnabled()) {
+                    log.debug("Application context not found. Can't reload")
+                }
+                return
+            }
+
+            GrailsControllerClass controllerClass = (GrailsControllerClass)application.addArtefact(ControllerArtefactHandler.TYPE, (Class)event.source)
+            beans {
+                "${controllerClass.fullName}"(controllerClass.clazz) { bean ->
+                    def beanScope = controllerClass.getScope()
+                    bean.scope = beanScope
+                    bean.autowire = "byName"
+                    if (beanScope == 'prototype') {
+                        bean.beanDefinition.dependencyCheck = AbstractBeanDefinition.DEPENDENCY_CHECK_NONE
+                    }
+                }
+            }
+        }
+    }
+
 }

grails-plugin-services/src/main/groovy/org/grails/plugins/services/ServicesGrailsPlugin.groovy

@@ -24,6 +24,8 @@ import grails.util.GrailsUtil
 import org.grails.core.artefact.ServiceArtefactHandler
 import org.grails.core.exceptions.GrailsConfigurationException
 
+import java.lang.reflect.Modifier
+
 
 /**
  * Configures services in the Spring context.
@@ -73,4 +75,29 @@ class ServicesGrailsPlugin extends Plugin  {
         serviceBeanAliasPostProcessor(ServiceBeanAliasPostProcessor)
     }}
 
+    void onChange(Map<String,Object> event) {
+        if (!event.source || !applicationContext) {
+            return
+        }
+
+        if (event.source instanceof Class) {
+            def application = grailsApplication
+            Class javaClass = event.source
+            // do nothing for abstract classes
+            if (Modifier.isAbstract(javaClass.modifiers)) return
+            def serviceClass = (GrailsServiceClass) application.addArtefact(ServiceArtefactHandler.TYPE, (Class) event.source)
+            def serviceName = "${serviceClass.propertyName}"
+            def scope = serviceClass.getPropertyValue("scope")
+
+            beans {
+                "$serviceName"(serviceClass.getClazz()) { bean ->
+                    bean.autowire = true
+                    if (scope) {
+                        bean.scope = scope
+                    }
+                }
+            }
+        }
+    }
+
 }

grails-plugin-url-mappings/src/main/groovy/org/grails/plugins/web/mapping/UrlMappingsGrailsPlugin.groovy

@@ -86,11 +86,46 @@ class UrlMappingsGrailsPlugin extends Plugin {
         urlMappingsErrorPageCustomizer(UrlMappingsErrorPageCustomizer)
         grailsLinkGenerator(cacheUrls ? CachingLinkGenerator : DefaultLinkGenerator, serverURL)
 
-        grailsUrlMappingsHolder(UrlMappingsHolderFactoryBean) { bean ->
-            bean.lazyInit = true
+        if (isReloadEnabled) {
+            urlMappingsTargetSource(HotSwappableTargetSourceFactoryBean) {
+                it.lazyInit = true
+                target = bean(UrlMappingsHolderFactoryBean) {
+                    it.lazyInit = true
+                }
+            }
+            grailsUrlMappingsHolder(ProxyFactoryBean) {
+                it.lazyInit = true
+                targetSource = urlMappingsTargetSource
+                proxyInterfaces = [UrlMappings]
+             }
+         } else {
+            grailsUrlMappingsHolder(UrlMappingsHolderFactoryBean) { bean ->
+                bean.lazyInit = true
+            }
         }
     }}
 
+    @Override
+    void onChange(Map<String, Object> event) {
+        def application = grailsApplication
+        if (!application.isArtefactOfType(UrlMappingsArtefactHandler.TYPE, event.source)) {
+            return
+        }
+
+        application.addArtefact(UrlMappingsArtefactHandler.TYPE, event.source)
+
+        ApplicationContext ctx = applicationContext
+        UrlMappingsHolder urlMappingsHolder = createUrlMappingsHolder(applicationContext)
+
+        HotSwappableTargetSource ts = ctx.getBean("urlMappingsTargetSource", HotSwappableTargetSource)
+        ts.swap urlMappingsHolder
+
+        LinkGenerator linkGenerator = ctx.getBean("grailsLinkGenerator", LinkGenerator)
+        if (linkGenerator instanceof CachingLinkGenerator) {
+          linkGenerator.clearCache()
+       }
+    }
+
     @CompileStatic
     private static UrlMappingsHolder createUrlMappingsHolder(ApplicationContext applicationContext) {
         def factory = new UrlMappingsHolderFactoryBean(applicationContext: applicationContext)