diff --git a/java/src/game/command/ArgumentParser.java b/java/src/game/command/ArgumentParser.java
index 6742b41..d961f69 100644
--- a/java/src/game/command/ArgumentParser.java
+++ b/java/src/game/command/ArgumentParser.java
@@ -1,5 +1,6 @@
 package game.command;
 
+import java.util.Collection;
 import java.util.List;
 
 import game.collect.Lists;
@@ -86,7 +87,7 @@ public abstract class ArgumentParser {
 
 	public abstract Object parse(CommandEnvironment env, String input);
 	public abstract Object getDefault(CommandEnvironment env);
-	public abstract String[] getCompletions(CommandEnvironment env);
+	public abstract Collection<String> getCompletions(CommandEnvironment env);
 	public abstract Class<?> getTypeClass();
 	
 	public final String getName() {
diff --git a/java/src/game/command/ArgumentSplitter.java b/java/src/game/command/ArgumentSplitter.java
index aa8ecb6..6d229e5 100644
--- a/java/src/game/command/ArgumentSplitter.java
+++ b/java/src/game/command/ArgumentSplitter.java
@@ -126,7 +126,7 @@ public class ArgumentSplitter {
 		return new ArgumentSplitter(args, str, env);
 	}
 	
-	private static String[] getParam(CommandEnvironment env, String[] argv, CachedExecutable cached) {
+	private static Iterable<String> getParam(CommandEnvironment env, String[] argv, CachedExecutable cached) {
 		Map<String, Parameter> parameters = cached.getParameters();
 		List<Parameter> positionals = Lists.newArrayList(cached.getPositionals());
 		Set<String> args = Sets.newHashSet();
@@ -190,16 +190,16 @@ public class ArgumentSplitter {
 		return null;
 	}
 	
-	public static String[] parseComplete(CommandEnvironment env, String[] argv, CachedExecutable cached, String last) {
-		String[] comp = getParam(env, argv, cached);
-		if(comp == null || comp.length == 0) {
+	public static Iterable<String> parseComplete(CommandEnvironment env, String[] argv, CachedExecutable cached, String last) {
+		Iterable<String> comp = getParam(env, argv, cached);
+		if(comp == null /* || comp.length == 0 */ ) {
 			Set<String> params = Sets.newTreeSet();
 			boolean all = last.startsWith("--");
 			for(String param : cached.getParameters().keySet()) {
 				if(all || param.length() == 1)
 					params.add(param.length() == 1 ? "-" + param : ("--" + param));
 			}
-			comp = params.toArray(new String[params.size()]);
+			return params;
 		}
 		return comp;
 	}
diff --git a/java/src/game/command/CommandEnvironment.java b/java/src/game/command/CommandEnvironment.java
index 7e1b555..a88ec0c 100644
--- a/java/src/game/command/CommandEnvironment.java
+++ b/java/src/game/command/CommandEnvironment.java
@@ -196,7 +196,7 @@ public class CommandEnvironment {
 			if(argv.length == 0)
 				return list;
 			String param = cmd.endsWith(" ") ? "" : argv[argv.length - 1];
-			String[] comp;
+			Iterable<String> comp;
 			if(argv.length > 1) {
 				int eq = argv[0].indexOf('=');
 				CachedExecutable cached = this.executables.get(eq >= 0 ? argv[0].substring(eq + 1) : argv[0]);
@@ -205,7 +205,7 @@ public class CommandEnvironment {
 				comp = ArgumentSplitter.parseComplete(this, argv, cached, param);
 			}
 			else {
-				comp = this.executables.keySet().toArray(new String[this.executables.keySet().size()]);
+				comp = this.executables.keySet();
 			}
 			for(String cmp : comp) {
 	            if(cmp.regionMatches(true, 0, param, 0, param.length()))
diff --git a/java/src/game/command/CompletingParser.java b/java/src/game/command/CompletingParser.java
index 99701c5..247c740 100644
--- a/java/src/game/command/CompletingParser.java
+++ b/java/src/game/command/CompletingParser.java
@@ -1,17 +1,21 @@
 package game.command;
 
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+
 public abstract class CompletingParser extends ArgumentParser {
-	private final String[] defCompletions;
+	private final List<String> defCompletions;
 	
 	public CompletingParser(String name, Object ... completions) {
 		super(name);
-		this.defCompletions = new String[completions.length];
-		for(int z = 0; z < completions.length; z++) {
-			this.defCompletions[z] = String.valueOf(completions[z]);
+		this.defCompletions = new ArrayList<String>(completions.length);
+		for(Object comp : completions) {
+			this.defCompletions.add(String.valueOf(comp));
 		}
 	}
 	
-	public String[] getCompletions(CommandEnvironment env) {
+	public Collection<String> getCompletions(CommandEnvironment env) {
 		return this.defCompletions;
 	}
 }
diff --git a/java/src/game/command/DimensionParser.java b/java/src/game/command/DimensionParser.java
index c0bfc72..f66ebf3 100644
--- a/java/src/game/command/DimensionParser.java
+++ b/java/src/game/command/DimensionParser.java
@@ -1,5 +1,7 @@
 package game.command;
 
+import java.util.Collection;
+
 import game.dimension.Dimension;
 import game.init.UniverseRegistry;
 import game.world.Position;
@@ -37,8 +39,8 @@ public class DimensionParser extends CompletingParser {
 //			throw new ScriptException("Unbekannte Dimension '%s'");
 	}
 	
-	public String[] getCompletions(CommandEnvironment env) {
-		return UniverseRegistry.getWorldNames().toArray(new String[UniverseRegistry.getWorldNames().size()]);
+	public Collection<String> getCompletions(CommandEnvironment env) {
+		return UniverseRegistry.getWorldNames();
 	}
 
 	public Class<?> getTypeClass() {
diff --git a/java/src/game/command/DoubleParser.java b/java/src/game/command/DoubleParser.java
index d3e32bb..19fec1f 100644
--- a/java/src/game/command/DoubleParser.java
+++ b/java/src/game/command/DoubleParser.java
@@ -1,5 +1,8 @@
 package game.command;
 
+import java.util.Collection;
+
+import game.collect.Lists;
 import game.world.BlockPos;
 import game.world.Position;
 
@@ -75,15 +78,15 @@ public class DoubleParser extends DefaultingParser {
 		return this.hasDefault() ? double.class : Double.class;
 	}
 	
-	public String[] getCompletions(CommandEnvironment env) {
+	public Collection<String> getCompletions(CommandEnvironment env) {
 		BlockPos pos = this.defType == null ? null : env.getExecutor().getPointedPosition();
 		switch(this.defType) {
 			case X:
-				return pos == null ? null : new String[] {"" + pos.getX()};
+				return pos == null ? null : Lists.newArrayList("" + pos.getX());
 			case Y:
-				return pos == null ? null : new String[] {"" + pos.getY()};
+				return pos == null ? null : Lists.newArrayList("" + pos.getY());
 			case Z:
-				return pos == null ? null : new String[] {"" + pos.getZ()};
+				return pos == null ? null : Lists.newArrayList("" + pos.getZ());
 		}
 		return super.getCompletions(env);
 	}
diff --git a/java/src/game/command/EntityListParser.java b/java/src/game/command/EntityListParser.java
index 9666024..3630cdd 100644
--- a/java/src/game/command/EntityListParser.java
+++ b/java/src/game/command/EntityListParser.java
@@ -1,5 +1,6 @@
 package game.command;
 
+import java.util.Collection;
 import java.util.List;
 import java.util.Set;
 
@@ -71,17 +72,15 @@ public class EntityListParser extends EntityParser {
 		return entity == null ? null : Lists.newArrayList(entity);
 	}
 	
-	public String[] getCompletions(CommandEnvironment env) {
-		Entity target = env.getExecutor().getPointedEntity();
-		List<String> comp = target == null || (this.livingOnly && !(target instanceof EntityLiving)) ? Lists.newArrayList() : Lists.newArrayList("#" + target.getId());
-		comp.addAll(env.getServer().getAllUsernames());
+	public Collection<String> getCompletions(CommandEnvironment env) {
+		Collection<String> comp = super.getCompletions(env);
 		comp.add("*");
 		for(Class<? extends Entity> clazz : EntityRegistry.getAllClasses()) {
 			if(!this.livingOnly || EntityLiving.class.isAssignableFrom(clazz))
 				comp.add(EntityRegistry.getEntityString(clazz));
 		}
 		comp.add("**");
-		return comp.toArray(new String[comp.size()]);
+		return comp;
 	}
 
 	public Class<?> getTypeClass() {
diff --git a/java/src/game/command/EntityParser.java b/java/src/game/command/EntityParser.java
index b4944c7..70d13b7 100644
--- a/java/src/game/command/EntityParser.java
+++ b/java/src/game/command/EntityParser.java
@@ -1,5 +1,6 @@
 package game.command;
 
+import java.util.Collection;
 import java.util.List;
 
 import game.collect.Lists;
@@ -46,11 +47,11 @@ public class EntityParser extends PlayerEntityParser {
 		return this.useSender && (this.livingOnly ? (env.getExecutor() instanceof EntityLiving) : (env.getExecutor() instanceof Entity)) ? env.getExecutor() : super.getDefault(env);
 	}
 	
-	public String[] getCompletions(CommandEnvironment env) {
+	public Collection<String> getCompletions(CommandEnvironment env) {
 		Entity target = env.getExecutor().getPointedEntity();
 		List<String> comp = target == null || (this.livingOnly && !(target instanceof EntityLiving)) ? Lists.newArrayList() : Lists.newArrayList("#" + target.getId());
-		comp.addAll(env.getServer().getAllUsernames());
-		return comp.toArray(new String[comp.size()]);
+		comp.addAll(super.getCompletions(env));
+		return comp;
 	}
 
 	public Class<?> getTypeClass() {
diff --git a/java/src/game/command/PlayerEntityListParser.java b/java/src/game/command/PlayerEntityListParser.java
index 0d768ee..008d86a 100644
--- a/java/src/game/command/PlayerEntityListParser.java
+++ b/java/src/game/command/PlayerEntityListParser.java
@@ -1,5 +1,6 @@
 package game.command;
 
+import java.util.Collection;
 import java.util.List;
 import game.collect.Lists;
 import game.entity.Entity;
@@ -30,10 +31,10 @@ public class PlayerEntityListParser extends PlayerEntityParser {
 		return entity == null ? null : Lists.newArrayList(entity);
 	}
 	
-	public String[] getCompletions(CommandEnvironment env) {
-		List<String> comp = Lists.newArrayList(env.getServer().getAllUsernames());
+	public Collection<String> getCompletions(CommandEnvironment env) {
+		Collection<String> comp = super.getCompletions(env);
 		comp.add("*");
-		return comp.toArray(new String[comp.size()]);
+		return comp;
 	}
 
 	public Class<?> getTypeClass() {
diff --git a/java/src/game/command/PlayerListParser.java b/java/src/game/command/PlayerListParser.java
index a142010..05857e8 100644
--- a/java/src/game/command/PlayerListParser.java
+++ b/java/src/game/command/PlayerListParser.java
@@ -1,5 +1,6 @@
 package game.command;
 
+import java.util.Collection;
 import java.util.List;
 import game.collect.Lists;
 import game.network.Player;
@@ -23,10 +24,10 @@ public class PlayerListParser extends PlayerParser {
 		return net == null ? null : Lists.newArrayList(net);
 	}
 	
-	public String[] getCompletions(CommandEnvironment env) {
-		List<String> comp = Lists.newArrayList(env.getServer().getAllUsernames());
+	public Collection<String> getCompletions(CommandEnvironment env) {
+		Collection<String> comp = super.getCompletions(env);
 		comp.add("*");
-		return comp.toArray(new String[comp.size()]);
+		return comp;
 	}
 
 	public Class<?> getTypeClass() {
diff --git a/java/src/game/command/PlayerParser.java b/java/src/game/command/PlayerParser.java
index c057bd1..0c5d7c8 100644
--- a/java/src/game/command/PlayerParser.java
+++ b/java/src/game/command/PlayerParser.java
@@ -1,7 +1,6 @@
 package game.command;
 
-import java.util.List;
-
+import java.util.Collection;
 import game.network.Player;
 
 public class PlayerParser extends CompletingParser {
@@ -23,9 +22,8 @@ public class PlayerParser extends CompletingParser {
 		return this.useSender && env.getExecutor() instanceof Player ? (Player)env.getExecutor() : null;
 	}
 	
-	public String[] getCompletions(CommandEnvironment env) {
-		List<String> comp = env.getServer().getAllUsernames();
-		return comp.toArray(new String[comp.size()]);
+	public Collection<String> getCompletions(CommandEnvironment env) {
+		return env.getServer().getAllUsernames();
 	}
 
 	public Class<?> getTypeClass() {
diff --git a/java/src/game/command/StringCompleter.java b/java/src/game/command/StringCompleter.java
index 97e99be..374bbb1 100644
--- a/java/src/game/command/StringCompleter.java
+++ b/java/src/game/command/StringCompleter.java
@@ -1,5 +1,7 @@
 package game.command;
 
+import java.util.Collection;
+
 public interface StringCompleter {
-	String[] complete(CommandEnvironment env);
+	Collection<String> complete(CommandEnvironment env);
 }
diff --git a/java/src/game/command/StringParser.java b/java/src/game/command/StringParser.java
index 93d55ae..1b3d636 100644
--- a/java/src/game/command/StringParser.java
+++ b/java/src/game/command/StringParser.java
@@ -1,5 +1,7 @@
 package game.command;
 
+import java.util.Collection;
+
 import game.util.CharValidator;
 
 public class StringParser extends DefaultingParser {
@@ -55,7 +57,7 @@ public class StringParser extends DefaultingParser {
 		return String.class;
 	}
 	
-	public String[] getCompletions(CommandEnvironment env) {
+	public Collection<String> getCompletions(CommandEnvironment env) {
 		return this.completer != null ? this.completer.complete(env) : super.getCompletions(env);
 	}
 }
diff --git a/java/src/game/command/WorldParser.java b/java/src/game/command/WorldParser.java
index 69b5e8a..c2df3bf 100644
--- a/java/src/game/command/WorldParser.java
+++ b/java/src/game/command/WorldParser.java
@@ -1,5 +1,6 @@
 package game.command;
 
+import java.util.Collection;
 import java.util.List;
 
 import game.collect.Lists;
@@ -31,13 +32,13 @@ public class WorldParser extends DimensionParser {
 //		return world;
 	}
 	
-	public String[] getCompletions(CommandEnvironment env) {
+	public Collection<String> getCompletions(CommandEnvironment env) {
 		if(this.loadedOnly) {
 			List<String> loaded = Lists.newArrayList();
 			for(WorldServer world : env.getServer().getWorlds()) {
 				loaded.add(world.dimension.getDimensionName());
 			}
-			return loaded.toArray(new String[loaded.size()]);
+			return loaded;
 		}
 		return super.getCompletions(env);
 	}
diff --git a/java/src/game/command/commands/CommandOfflinetp.java b/java/src/game/command/commands/CommandOfflinetp.java
index f638dec..7ad7c0a 100644
--- a/java/src/game/command/commands/CommandOfflinetp.java
+++ b/java/src/game/command/commands/CommandOfflinetp.java
@@ -1,7 +1,9 @@
 package game.command.commands;
 
+import java.util.Collection;
 import java.util.List;
 import game.command.CommandEnvironment;
+import game.collect.Lists;
 import game.command.Command;
 import game.command.Executor;
 import game.command.RunException;
@@ -16,8 +18,8 @@ public class CommandOfflinetp extends Command {
 		super("offlinetp");
 		
 		this.addString("user", false, new StringCompleter() {
-			public String[] complete(CommandEnvironment env) {
-				return env.getServer().getUsers();
+			public Collection<String> complete(CommandEnvironment env) {
+				return Lists.newArrayList(env.getServer().getUsers());
 			}
 		});
 		
diff --git a/java/src/game/command/commands/CommandWarp.java b/java/src/game/command/commands/CommandWarp.java
index 0fa9fa0..04f8a03 100644
--- a/java/src/game/command/commands/CommandWarp.java
+++ b/java/src/game/command/commands/CommandWarp.java
@@ -1,7 +1,9 @@
 package game.command.commands;
 
+import java.util.Collection;
 import java.util.List;
 import game.command.CommandEnvironment;
+import game.collect.Lists;
 import game.command.Command;
 import game.command.Executor;
 import game.command.RunException;
@@ -18,13 +20,9 @@ public class CommandWarp extends Command {
 		super("warp");
 		
 		this.addString("warp", true, new StringCompleter() {
-			public String[] complete(CommandEnvironment env) {
-				String[] warps = new String[1 + env.getServer().getWarps().size()];
-				warps[0] = "spawn";
-				int pos = 1;
-				for(String warp : env.getServer().getWarps().keySet()) {
-					warps[pos++] = warp;
-				}
+			public Collection<String> complete(CommandEnvironment env) {
+				List<String> warps = Lists.newArrayList("spawn");
+				warps.addAll(env.getServer().getWarps().keySet());
 				return warps;
 			}
 		});