diff --git a/src/main/java/net/minecraft/server/JsonList.java b/src/main/java/net/minecraft/server/JsonList.java
new file mode 100644
index 0000000000..36df988832
--- /dev/null
+++ b/src/main/java/net/minecraft/server/JsonList.java
@@ -0,0 +1,160 @@
+package net.minecraft.server;
+
+import java.io.BufferedReader;
+import java.io.BufferedWriter;
+import java.io.File;
+import java.io.IOException;
+import java.lang.reflect.ParameterizedType;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Iterator;
+import java.util.Map;
+
+import net.minecraft.util.com.google.common.base.Charsets;
+import net.minecraft.util.com.google.common.collect.Lists;
+import net.minecraft.util.com.google.common.collect.Maps;
+import net.minecraft.util.com.google.common.io.Files;
+import net.minecraft.util.com.google.gson.Gson;
+import net.minecraft.util.com.google.gson.GsonBuilder;
+import net.minecraft.util.com.google.gson.JsonObject;
+import net.minecraft.util.org.apache.commons.io.IOUtils;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+
+public class JsonList {
+
+    protected static final Logger a = LogManager.getLogger();
+    protected final Gson b;
+    private final File c;
+    private final Map d = Maps.newHashMap();
+    private boolean e = true;
+    private static final ParameterizedType f = new JsonListType();
+
+    public JsonList(File file1) {
+        this.c = file1;
+        GsonBuilder gsonbuilder = (new GsonBuilder()).setPrettyPrinting();
+
+        gsonbuilder.registerTypeHierarchyAdapter(JsonListEntry.class, new JsonListEntrySerializer(this, (JsonListType) null));
+        this.b = gsonbuilder.create();
+    }
+
+    public boolean isEnabled() {
+        return this.e;
+    }
+
+    public void a(boolean flag) {
+        this.e = flag;
+    }
+
+    public File c() {
+        return this.c;
+    }
+
+    public void add(JsonListEntry jsonlistentry) {
+        this.d.put(this.a(jsonlistentry.f()), jsonlistentry);
+
+        try {
+            this.save();
+        } catch (IOException ioexception) {
+            a.warn("Could not save the list after adding a user.", ioexception);
+        }
+    }
+
+    public JsonListEntry get(Object object) {
+        this.h();
+        return (JsonListEntry) this.d.get(this.a(object));
+    }
+
+    public void remove(Object object) {
+        this.d.remove(this.a(object));
+
+        try {
+            this.save();
+        } catch (IOException ioexception) {
+            a.warn("Could not save the list after removing a user.", ioexception);
+        }
+    }
+
+    public String[] getEntries() {
+        return (String[]) this.d.keySet().toArray(new String[this.d.size()]);
+    }
+
+    public boolean d() {
+        return this.d.size() < 1;
+    }
+
+    protected String a(Object object) {
+        return object.toString();
+    }
+
+    protected boolean d(Object object) {
+        return this.d.containsKey(this.a(object));
+    }
+
+    private void h() {
+        ArrayList arraylist = Lists.newArrayList();
+        Iterator iterator = this.d.values().iterator();
+
+        while (iterator.hasNext()) {
+            JsonListEntry jsonlistentry = (JsonListEntry) iterator.next();
+
+            if (jsonlistentry.e()) {
+                arraylist.add(jsonlistentry.f());
+            }
+        }
+
+        iterator = arraylist.iterator();
+
+        while (iterator.hasNext()) {
+            Object object = iterator.next();
+
+            this.d.remove(object);
+        }
+    }
+
+    protected JsonListEntry a(JsonObject jsonobject) {
+        return new JsonListEntry(null, jsonobject);
+    }
+
+    protected Map e() {
+        return this.d;
+    }
+
+    public void save() {
+        Collection collection = this.d.values();
+        String s = this.b.toJson(collection);
+        BufferedWriter bufferedwriter = null;
+
+        try {
+            bufferedwriter = Files.newWriter(this.c, Charsets.UTF_8);
+            bufferedwriter.write(s);
+        } finally {
+            IOUtils.closeQuietly(bufferedwriter);
+        }
+    }
+
+    public void load() {
+        Collection collection = null;
+        BufferedReader bufferedreader = null;
+
+        try {
+            bufferedreader = Files.newReader(this.c, Charsets.UTF_8);
+            collection = (Collection) this.b.fromJson(bufferedreader, f);
+        } finally {
+            IOUtils.closeQuietly(bufferedreader);
+        }
+
+        if (collection != null) {
+            this.d.clear();
+            Iterator iterator = collection.iterator();
+
+            while (iterator.hasNext()) {
+                JsonListEntry jsonlistentry = (JsonListEntry) iterator.next();
+
+                if (jsonlistentry.f() != null) {
+                    this.d.put(this.a(jsonlistentry.f()), jsonlistentry);
+                }
+            }
+        }
+    }
+}
diff --git a/src/main/java/net/minecraft/server/JsonListEntry.java b/src/main/java/net/minecraft/server/JsonListEntry.java
new file mode 100644
index 0000000000..3a7e2c3825
--- /dev/null
+++ b/src/main/java/net/minecraft/server/JsonListEntry.java
@@ -0,0 +1,26 @@
+package net.minecraft.server;
+
+import net.minecraft.util.com.google.gson.JsonObject;
+
+public class JsonListEntry {
+
+    private final Object a;
+
+    public JsonListEntry(Object object) {
+        this.a = object;
+    }
+
+    protected JsonListEntry(Object object, JsonObject jsonobject) {
+        this.a = object;
+    }
+
+    Object f() {
+        return this.a;
+    }
+
+    boolean e() {
+        return false;
+    }
+
+    protected void a(JsonObject jsonobject) {}
+}
diff --git a/src/main/java/net/minecraft/server/JsonListEntrySerializer.java b/src/main/java/net/minecraft/server/JsonListEntrySerializer.java
new file mode 100644
index 0000000000..b6aba6a60c
--- /dev/null
+++ b/src/main/java/net/minecraft/server/JsonListEntrySerializer.java
@@ -0,0 +1,49 @@
+package net.minecraft.server;
+
+import java.lang.reflect.Type;
+
+import net.minecraft.util.com.google.gson.JsonDeserializationContext;
+import net.minecraft.util.com.google.gson.JsonDeserializer;
+import net.minecraft.util.com.google.gson.JsonElement;
+import net.minecraft.util.com.google.gson.JsonObject;
+import net.minecraft.util.com.google.gson.JsonSerializationContext;
+import net.minecraft.util.com.google.gson.JsonSerializer;
+
+class JsonListEntrySerializer implements JsonDeserializer, JsonSerializer {
+
+    final JsonList a;
+
+    private JsonListEntrySerializer(JsonList jsonlist) {
+        this.a = jsonlist;
+    }
+
+    public JsonElement a(JsonListEntry jsonlistentry, Type type, JsonSerializationContext jsonserializationcontext) {
+        JsonObject jsonobject = new JsonObject();
+
+        jsonlistentry.a(jsonobject);
+        return jsonobject;
+    }
+
+    public JsonListEntry a(JsonElement jsonelement, Type type, JsonDeserializationContext jsondeserializationcontext) {
+        if (jsonelement.isJsonObject()) {
+            JsonObject jsonobject = jsonelement.getAsJsonObject();
+            JsonListEntry jsonlistentry = this.a.a(jsonobject);
+
+            return jsonlistentry;
+        } else {
+            return null;
+        }
+    }
+
+    public JsonElement serialize(Object object, Type type, JsonSerializationContext jsonserializationcontext) {
+        return this.a((JsonListEntry) object, type, jsonserializationcontext);
+    }
+
+    public Object deserialize(JsonElement jsonelement, Type type, JsonDeserializationContext jsondeserializationcontext) {
+        return this.a(jsonelement, type, jsondeserializationcontext);
+    }
+
+    JsonListEntrySerializer(JsonList jsonlist, JsonListType jsonlisttype) {
+        this(jsonlist);
+    }
+}