fix: add support for Vaadin 25.1

In Vaadin 25.1, hotswap-related classes have been moved into a different
module with a different package name.
This change updates the Hotswap Agent plugin to support the updates in
Vaadin 25.1 in a backward-compatible manner.

Author: mcollovati

plugin/hotswap-agent-vaadin-plugin/src/main/java/org/hotswap/agent/plugin/vaadin/VaadinPlugin.java

@@ -139,7 +139,7 @@ public void initPlugin() {
     @OnClassLoadEvent(classNameRegexp = VAADIN_SERVLET)
     public static void init(CtClass ctClass, ClassPool classPool)
             throws NotFoundException, CannotCompileException {
-        boolean hasVaadinHotSwapper = classPool.getOrNull("com.vaadin.flow.hotswap.Hotswapper") != null;
+        boolean hasVaadinHotSwapper = findHotswapperClass(classPool) != null;
 
         String src = PluginManagerInvoker
                 .buildInitializePlugin(VaadinPlugin.class);
@@ -156,15 +156,19 @@ public static void init(CtClass ctClass, ClassPool classPool)
     @OnClassLoadEvent(classNameRegexp = VAADIN_SERVICE)
     public static void transformVaadinService(CtClass ctClass, ClassPool classPool)
             throws NotFoundException, CannotCompileException {
-        boolean hasVaadinHotSwapper = classPool.getOrNull("com.vaadin.flow.hotswap.Hotswapper") != null;
+
+        CtClass vaadinHotSwapper = findHotswapperClass(classPool);
+        boolean hasVaadinHotSwapper = vaadinHotSwapper != null;
 
         StringBuilder src = new StringBuilder();
         if (hasVaadinHotSwapper) {
             String initHotswapperPluginCall = PluginManagerInvoker.buildCallPluginMethod(
                     VaadinPlugin.class, "initializeHotswapper", "hotswapper",
                     "java.lang.Object");
             src.append("try { ")
-                    .append("java.util.Optional maybeHotswapper = com.vaadin.flow.hotswap.Hotswapper.register(this);")
+                    .append("java.util.Optional maybeHotswapper = ")
+                    .append(vaadinHotSwapper.getName())
+                    .append(".register(this);")
                     .append("if (maybeHotswapper.isPresent()) { ")
                     .append("Object hotswapper = maybeHotswapper.get();")
                     .append(initHotswapperPluginCall)
@@ -184,6 +188,16 @@ public static void transformVaadinService(CtClass ctClass, ClassPool classPool)
 
     }
 
+    private static CtClass findHotswapperClass(ClassPool classPool) {
+        // Since Vaadin 25.1
+        CtClass vaadinHotSwapper = classPool.getOrNull("com.vaadin.base.devserver.hotswap.Hotswapper");
+        if (vaadinHotSwapper == null) {
+            // Until Vaadin 25.0
+            vaadinHotSwapper = classPool.getOrNull("com.vaadin.flow.hotswap.Hotswapper");
+        }
+        return vaadinHotSwapper;
+    }
+
     public void registerServlet(Object vaadinServlet) {
         try {
             Class<?> vaadinIntegrationClass = resolveClass("org.hotswap.agent.plugin.vaadin.VaadinIntegration");