Merge branch 'master' of https://github.com/astei/velocity into config

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

@@ -112,6 +112,7 @@ public class VelocityServer implements ProxyServer {
 
             if (!configuration.validate()) {
                 logger.error("Your configuration is invalid. Velocity will refuse to start up until the errors are resolved.");
+                LogManager.shutdown();
                 System.exit(1);
             }
 
@@ -119,6 +120,7 @@ public class VelocityServer implements ProxyServer {
 
         } catch (IOException | RuntimeException e) {
             logger.error("Unable to load your velocity.toml. The server will shut down.", e);
+            LogManager.shutdown();
             System.exit(1);
         }
 

proxy/src/main/java/com/velocitypowered/proxy/scheduler/VelocityScheduler.java

@@ -12,7 +12,8 @@ import com.velocitypowered.api.scheduler.TaskStatus;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 
-import java.util.ArrayList;
+import java.util.Collection;
+import java.util.HashSet;
 import java.util.IdentityHashMap;
 import java.util.concurrent.*;
 import java.util.concurrent.atomic.AtomicReference;
@@ -21,8 +22,8 @@ public class VelocityScheduler implements Scheduler {
     private final PluginManager pluginManager;
     private final ExecutorService taskService;
     private final ScheduledExecutorService timerExecutionService;
-    private final Multimap<Object, ScheduledTask> tasksByPlugin = Multimaps.synchronizedListMultimap(
+    private final Multimap<Object, ScheduledTask> tasksByPlugin = Multimaps.synchronizedMultimap(
-            Multimaps.newListMultimap(new IdentityHashMap<>(), ArrayList::new));
+            Multimaps.newSetMultimap(new IdentityHashMap<>(), HashSet::new));
 
     public VelocityScheduler(PluginManager pluginManager) {
         this.pluginManager = pluginManager;
@@ -41,7 +42,11 @@ public class VelocityScheduler implements Scheduler {
     }
 
     public boolean shutdown() throws InterruptedException {
-        for (ScheduledTask task : ImmutableList.copyOf(tasksByPlugin.values())) {
+        Collection<ScheduledTask> terminating;
+        synchronized (tasksByPlugin) {
+            terminating = ImmutableList.copyOf(tasksByPlugin.values());
+        }
+        for (ScheduledTask task : terminating) {
             task.cancel();
         }
         timerExecutionService.shutdown();