--- a/net/minecraft/server/EntitySlice.java
+++ b/net/minecraft/server/EntitySlice.java
@@ -13,7 +13,7 @@
 
 public class EntitySlice<T> extends AbstractSet<T> {
 
-    private static final Set<Class<?>> a = Sets.newHashSet();
+    private static final Set<Class<?>> a = Sets.newConcurrentHashSet(); // CraftBukkit
     private final Map<Class<?>, List<T>> b = Maps.newHashMap();
     private final Set<Class<?>> c = Sets.newIdentityHashSet();
     private final Class<T> d;
@@ -35,7 +35,7 @@
 
     protected void a(Class<?> oclass) {
         EntitySlice.a.add(oclass);
-        Iterator iterator = this.e.iterator();
+        Iterator<T> iterator = this.e.iterator(); // CraftBukkit - decompile error
 
         while (iterator.hasNext()) {
             T t0 = iterator.next();
@@ -78,7 +78,7 @@
         List<T> list = (List) this.b.get(oclass);
 
         if (list == null) {
-            this.b.put(oclass, Lists.newArrayList(new Object[] { t0}));
+            this.b.put(oclass, Lists.newArrayList(t0));
         } else {
             list.add(t0);
         }
@@ -86,7 +86,7 @@
     }
 
     public boolean remove(Object object) {
-        T t0 = object;
+        T t0 = (T) object; // CraftBukkit - decompile error
         boolean flag = false;
         Iterator iterator = this.c.iterator();