Some classloader/dependency versioning fix ups

proxy/src/main/java/com/velocitypowered/proxy/VelocityServer.java

@@ -343,7 +343,7 @@ public class VelocityServer implements ProxyServer, ForwardingAudience {
       }
     }
 
-    logger.info("Loaded {} plugins", pluginManager.plugins().size());
+    logger.info("Loaded {} plugin(s)", pluginManager.plugins().size() - 1);
   }
 
   public Bootstrap createBootstrap(@Nullable EventLoopGroup group, SocketAddress target) {

proxy/src/main/java/com/velocitypowered/proxy/plugin/PluginClassLoader.java

@@ -36,8 +36,8 @@ public class PluginClassLoader extends URLClassLoader {
 
   private final PluginDescription description;
 
-  public PluginClassLoader(URL[] urls, PluginDescription description) {
+  public PluginClassLoader(URL[] urls, ClassLoader parent, PluginDescription description) {
-    super(urls);
+    super(urls, parent);
     this.description = description;
   }
 
@@ -60,14 +60,18 @@ public class PluginClassLoader extends URLClassLoader {
   }
 
   @Override
-  protected Class<?> loadClass(String name, boolean resolve) throws ClassNotFoundException {
+  protected Class<?> findClass(String name) throws ClassNotFoundException {
-    return loadClass0(name, resolve, true);
+    return findClass0(name, true);
   }
 
-  private Class<?> loadClass0(String name, boolean resolve, boolean checkOther)
+  private Class<?> findClass0(String name, boolean checkOther)
       throws ClassNotFoundException {
+    if (name.startsWith("com.velocitypowered")) {
+      throw new ClassNotFoundException();
+    }
+
     try {
-      return super.loadClass(name, resolve);
+      return super.findClass(name);
     } catch (ClassNotFoundException ignored) {
       // Ignored: we'll try others
     }
@@ -76,7 +80,7 @@ public class PluginClassLoader extends URLClassLoader {
       for (PluginClassLoader loader : loaders) {
         if (loader != this) {
           try {
-            return loader.loadClass0(name, resolve, false);
+            return loader.findClass0(name, false);
           } catch (ClassNotFoundException ignored) {
             // We're trying others, safe to ignore
           }

proxy/src/main/java/com/velocitypowered/proxy/plugin/VelocityPluginManager.java

@@ -136,7 +136,7 @@ public class VelocityPluginManager implements PluginManager {
               Semver dependencyCandidateVersion = new Semver(
                   dependencyContainer.description().version(), SemverType.NPM);
               if (!dependencyCandidateVersion.satisfies(requiredRange)) {
-                if (dependency.optional()) {
+                if (!dependency.optional()) {
                   logger.error(
                       "Can't load plugin {} due to incompatible dependency {} {} (you have {})",
                       candidate.id(), dependency.id(), requiredRange,

proxy/src/main/java/com/velocitypowered/proxy/plugin/loader/java/JavaPluginLoader.java

@@ -92,7 +92,7 @@ public class JavaPluginLoader implements PluginLoader {
     PluginClassLoader loader = this.classLoaders.computeIfAbsent(pluginJarUri, (uri) -> {
       PluginClassLoader classLoader = AccessController.doPrivileged(
           (PrivilegedAction<PluginClassLoader>) () -> new PluginClassLoader(new URL[]{pluginJarUrl},
-              source));
+              JavaPluginLoader.class.getClassLoader(), source));
       classLoader.addToClassloaders();
       return classLoader;
     });