Some fixes (#165)

proxy/src/main/java/com/velocitypowered/proxy/command/VelocityCommandManager.java

@@ -47,13 +47,13 @@ public class VelocityCommandManager implements CommandManager {
     }
 
     String alias = split[0];
-    @SuppressWarnings("nullness")
-    String[] actualArgs = Arrays.copyOfRange(split, 1, split.length);
     Command command = commands.get(alias.toLowerCase(Locale.ENGLISH));
     if (command == null) {
       return false;
     }
 
+    @SuppressWarnings("nullness")
+    String[] actualArgs = Arrays.copyOfRange(split, 1, split.length);
     try {
       if (!command.hasPermission(source, actualArgs)) {
         return false;
@@ -103,14 +103,14 @@ public class VelocityCommandManager implements CommandManager {
       return availableCommands;
     }
 
-    @SuppressWarnings("nullness")
-    String[] actualArgs = Arrays.copyOfRange(split, 1, split.length);
     Command command = commands.get(alias.toLowerCase(Locale.ENGLISH));
     if (command == null) {
       // No such command, so we can't offer any tab complete suggestions.
       return ImmutableList.of();
     }
 
+    @SuppressWarnings("nullness")
+    String[] actualArgs = Arrays.copyOfRange(split, 1, split.length);
     try {
       if (!command.hasPermission(source, actualArgs)) {
         return ImmutableList.of();
@@ -140,14 +140,14 @@ public class VelocityCommandManager implements CommandManager {
     }
 
     String alias = split[0];
-    @SuppressWarnings("nullness")
-    String[] actualArgs = Arrays.copyOfRange(split, 1, split.length);
     Command command = commands.get(alias.toLowerCase(Locale.ENGLISH));
     if (command == null) {
       // No such command.
       return false;
     }
 
+    @SuppressWarnings("nullness")
+    String[] actualArgs = Arrays.copyOfRange(split, 1, split.length);
     try {
       return command.hasPermission(source, actualArgs);
     } catch (Exception e) {

proxy/src/main/java/com/velocitypowered/proxy/connection/MinecraftConnection.java

@@ -24,7 +24,6 @@ import com.velocitypowered.proxy.protocol.netty.MinecraftCompressDecoder;
 import com.velocitypowered.proxy.protocol.netty.MinecraftCompressEncoder;
 import com.velocitypowered.proxy.protocol.netty.MinecraftDecoder;
 import com.velocitypowered.proxy.protocol.netty.MinecraftEncoder;
-import com.velocitypowered.proxy.protocol.packet.Disconnect;
 import io.netty.buffer.ByteBuf;
 import io.netty.channel.Channel;
 import io.netty.channel.ChannelFutureListener;
@@ -136,7 +135,11 @@ public class MinecraftConnection extends ChannelInboundHandlerAdapter {
   public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
     if (ctx.channel().isActive()) {
       if (sessionHandler != null) {
-        sessionHandler.exception(cause);
+        try {
+          sessionHandler.exception(cause);
+        } catch (Exception ex) {
+          logger.error("{}: exception handling exception", (association != null ? association : channel.remoteAddress()), cause);
+        }
       }
 
       if (association != null) {

proxy/src/main/java/com/velocitypowered/proxy/connection/backend/VelocityServerConnection.java

@@ -117,7 +117,7 @@ public class VelocityServerConnection implements MinecraftConnectionAssociation,
     // BungeeCord IP forwarding is simply a special injection after the "address" in the handshake,
     // separated by \0 (the null byte). In order, you send the original host, the player's IP, their
     // UUID (undashed), and if you are in online-mode, their login properties (from Mojang).
-    StringBuilder data = new StringBuilder(2048)
+    StringBuilder data = new StringBuilder()
         .append(registeredServer.getServerInfo().getAddress().getHostString())
         .append('\0')
         .append(proxyPlayer.getRemoteAddress().getHostString())

proxy/src/main/java/com/velocitypowered/proxy/network/http/SimpleHttpResponseCollector.java

@@ -13,7 +13,7 @@ import java.util.concurrent.CompletableFuture;
 
 class SimpleHttpResponseCollector extends ChannelInboundHandlerAdapter {
 
-  private final StringBuilder buffer = new StringBuilder(1024);
+  private final StringBuilder buffer = new StringBuilder();
   private final CompletableFuture<SimpleHttpResponse> reply;
   private int httpCode;
   private boolean canKeepAlive;

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

@@ -1,5 +1,6 @@
 package com.velocitypowered.proxy.plugin;
 
+import java.io.IOException;
 import java.net.MalformedURLException;
 import java.net.URL;
 import java.net.URLClassLoader;
@@ -31,6 +32,12 @@ public class PluginClassLoader extends URLClassLoader {
     }
   }
 
+  @Override
+  public void close() throws IOException {
+    loaders.remove(this);
+    super.close();
+  }
+
   @Override
   protected Class<?> loadClass(String name, boolean resolve) throws ClassNotFoundException {
     return loadClass0(name, resolve, true);

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

@@ -41,9 +41,7 @@ public class VelocityPluginManager implements PluginManager {
   private void registerPlugin(PluginContainer plugin) {
     plugins.put(plugin.getDescription().getId(), plugin);
     Optional<?> instance = plugin.getInstance();
-    if (instance.isPresent()) {
+    instance.ifPresent(o -> pluginInstances.put(o, plugin));
-      pluginInstances.put(instance.get(), plugin);
-    }
   }
 
   /**