Make showBlock(s) thread-safe.

src/com/garbagemule/MobArena/region/ArenaRegion.java

@@ -644,7 +644,10 @@ public class ArenaRegion
         showBlocks(p, map.values());
     }
 
-    public void showBlock(final Player p, final Location loc, int id, byte data) {
+    public void showBlock(final Player p, final Location loc, final int id, final byte data) {
+        arena.scheduleTask(new Runnable() {
+            @Override
+            public void run() {
                 p.sendBlockChange(loc, id, data);
                 arena.scheduleTask(new Runnable() {
                     @Override
@@ -656,8 +659,13 @@ public class ArenaRegion
                     }
                 }, 100);
             }
+        }, 0);
+    }
 
-    private void showBlocks(final Player p, Collection<Location> points) {
+    private void showBlocks(final Player p, final Collection<Location> points) {
+        arena.scheduleTask(new Runnable() {
+            @Override
+            public void run() {
                 // Grab all the blocks, and send block change events.
                 final Map<Location,BlockState> blocks = new HashMap<Location,BlockState>();
                 for (Location l : points) {
@@ -665,7 +673,6 @@ public class ArenaRegion
                     blocks.put(l, b.getState());
                     p.sendBlockChange(l, 35, (byte) 14);
                 }
-
                 arena.scheduleTask(new Runnable() {
                     public void run() {
                         // If the player isn't online, just forget it.
@@ -685,6 +692,8 @@ public class ArenaRegion
                     }
                 }, 100);
             }
+        }, 0);
+    }
 
     private List<Location> getFramePoints(Location loc1, Location loc2) {
         List<Location> result = new ArrayList<Location>();