Sort server.properties while writing.

patches/minecraft/net/minecraft/server/dedicated/PropertyManager.java.patch

@@ -0,0 +1,11 @@
+--- a/net/minecraft/server/dedicated/PropertyManager.java
++++ b/net/minecraft/server/dedicated/PropertyManager.java
+@@ -38,7 +38,7 @@
+ 
+    public void func_218970_c(Path p_218970_1_) {
+       try (OutputStream outputstream = Files.newOutputStream(p_218970_1_)) {
+-         this.field_73672_b.store(outputstream, "Minecraft server properties");
++         net.minecraftforge.common.util.SortedProperties.store(field_73672_b, outputstream, "Minecraft server properties");
+       } catch (IOException var15) {
+          field_164440_a.error("Failed to store properties to file: " + p_218970_1_);
+       }

src/main/java/net/minecraftforge/common/util/SortedProperties.java

@@ -0,0 +1,67 @@
+/*
+ * Minecraft Forge
+ * Copyright (c) 2016-2019.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation version 2.1
+ * of the License.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+package net.minecraftforge.common.util;
+
+import java.io.IOException;
+import java.io.OutputStream;
+import java.util.Collections;
+import java.util.Enumeration;
+import java.util.Map;
+import java.util.Properties;
+import java.util.Set;
+import java.util.TreeSet;
+
+/**
+ * An Implementation of Properties that is sorted when iterating.
+ * Made because i got tired of seeing config files written in random orders.
+ * This is implemented very basically, and thus is not a speedy system.
+ * This is not recommended for used in high traffic areas, and is mainly intended for writing to disc.
+ */
+public class SortedProperties extends Properties
+{
+    private static final long serialVersionUID = -8913480931455982442L;
+
+    @Override
+    public Set<Map.Entry<Object, Object>> entrySet()
+    {
+        Set<Map.Entry<Object, Object>> ret = new TreeSet<>((left, right) -> left.getKey().toString().compareTo(right.getKey().toString()));
+        ret.addAll(super.entrySet());
+        return ret;
+    }
+
+    @Override
+    public Set<Object> keySet()
+    {
+        return new TreeSet<>(super.keySet());
+    }
+
+    @Override
+    public synchronized Enumeration<Object> keys()
+    {
+        return Collections.enumeration(new TreeSet<>(super.keySet()));
+    }
+
+    public static void store(Properties props, OutputStream stream, String comment) throws IOException
+    {
+        SortedProperties sorted = new SortedProperties();
+        sorted.putAll(props);
+        sorted.store(stream, comment);
+    }
+}