Add basis of grouped thread factory and make the scheduler use it.

api/src/main/java/net/md_5/bungee/api/plugin/Plugin.java

@@ -1,11 +1,16 @@
 package net.md_5.bungee.api.plugin;
 
+import com.google.common.util.concurrent.ThreadFactoryBuilder;
 import java.io.File;
 import java.io.InputStream;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ThreadFactory;
 import java.util.logging.Logger;
 import lombok.Getter;
 import net.md_5.bungee.api.ProxyServer;
 import net.md_5.bungee.api.config.ConfigurationAdapter;
+import net.md_5.bungee.api.scheduler.GroupedThreadFactory;
 
 /**
  * Represents any Plugin that may be loaded at runtime to enhance existing
@@ -83,4 +88,19 @@ public class Plugin
         this.file = description.getFile();
         this.logger = new PluginLogger( this );
     }
+
+    //
+    private ExecutorService service;
+
+    @Deprecated
+    public ExecutorService getExecutorService()
+    {
+        if ( service == null )
+        {
+            service = Executors.newCachedThreadPool( new ThreadFactoryBuilder().setNameFormat( getDescription().getName() + " Pool Thread #%1$d" )
+                    .setThreadFactory( new GroupedThreadFactory( this ) ).build() );
+        }
+        return service;
+    }
+    //
 }

api/src/main/java/net/md_5/bungee/api/scheduler/GroupedThreadFactory.java

@@ -0,0 +1,34 @@
+package net.md_5.bungee.api.scheduler;
+
+import java.util.concurrent.ThreadFactory;
+import lombok.Data;
+import net.md_5.bungee.api.plugin.Plugin;
+
+@Data
+@Deprecated
+public class GroupedThreadFactory implements ThreadFactory
+{
+
+    private final ThreadGroup group;
+
+    public class BungeeGroup extends ThreadGroup
+    {
+
+        private BungeeGroup(String name)
+        {
+            super( name );
+        }
+
+    }
+
+    public GroupedThreadFactory(Plugin plugin)
+    {
+        this.group = new BungeeGroup( plugin.getDescription().getName() );
+    }
+
+    @Override
+    public Thread newThread(Runnable r)
+    {
+        return new Thread( group, r );
+    }
+}