Fixed a further exploit with players attacking more things that they shouldn't.

src/main/java/net/minecraft/server/EntityPlayer.java

@@ -648,7 +648,7 @@ public class EntityPlayer extends EntityHuman implements ICrafting {
         this.deathTicks = 0;
         effects.clear();
         this.activeContainer = this.defaultContainer;
-        this.lastSentExp = -1; // lastSentExp. Find line: "if (this.expTotal != this.XXXX) {"
+        this.lastSentExp = -1;
         if(this.keepLevel) {
             this.exp = exp;
         } else {

src/main/java/net/minecraft/server/NetServerHandler.java

@@ -923,9 +923,10 @@ public class NetServerHandler extends NetHandler implements ICommandListener {
                     this.player.updateInventory(this.player.activeContainer);
                 }
             } else if (packet7useentity.c == 1) {
-                if (entity instanceof EntityItem) {
-                    disconnect("Attacking an item is not permitted");
-                    System.out.println("Player " + player.name + " tried to attack an item entity, so I have disconnected them for exploiting.");
+                if ((entity instanceof EntityItem) || (entity instanceof EntityExperienceOrb) || (entity instanceof EntityArrow)) {
+                    String type = entity.getClass().getSimpleName();
+                    disconnect("Attacking an " + type + " is not permitted");
+                    System.out.println("Player " + player.name + " tried to attack an " + type + ", so I have disconnected them for exploiting.");
                     return;
                 }