Things. they work. Obviously still WAY more to do.

src/main/java/net/minecraftforge/fml/AutomaticEventSubscriber.java

@@ -0,0 +1,73 @@
+/*
+ * Minecraft Forge
+ * Copyright (c) 2018.
+ *
+ * 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.fml;
+
+import net.minecraftforge.api.Side;
+import net.minecraftforge.common.MinecraftForge;
+import net.minecraftforge.fml.common.Mod;
+import net.minecraftforge.fml.ModContainer;
+import net.minecraftforge.fml.language.ModFileScanData;
+import net.minecraftforge.fml.loading.FMLEnvironment;
+import net.minecraftforge.fml.loading.moddiscovery.ModAnnotation;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.objectweb.asm.Type;
+
+import java.util.EnumSet;
+import java.util.List;
+import java.util.Objects;
+import java.util.stream.Collectors;
+
+import static net.minecraftforge.fml.Logging.LOADING;
+
+/**
+ * Automatic eventbus subscriber - reads {@link net.minecraftforge.fml.common.Mod.EventBusSubscriber}
+ * annotations and passes the class instances to the {@link net.minecraftforge.common.MinecraftForge.EVENT_BUS}
+ */
+public class AutomaticEventSubscriber
+{
+    private static final Logger LOGGER = LogManager.getLogger("FML");
+    public static void inject(final ModContainer mod, final ModFileScanData scanData, final ClassLoader loader)
+    {
+        LOGGER.debug(LOADING,"Attempting to inject @EventBusSubscriber classes into the eventbus for {}", mod.getModId());
+        List<ModFileScanData.AnnotationData> ebsTargets = scanData.getAnnotations().stream().
+                filter(annotationData -> Objects.equals(annotationData.getAnnotationType(), Type.getType(Mod.EventBusSubscriber.class))).
+                collect(Collectors.toList());
+
+        ebsTargets.forEach(ad -> {
+            final List<ModAnnotation.EnumHolder> sidesValue = (List<ModAnnotation.EnumHolder>)ad.getAnnotationData().get("value");
+            final EnumSet<Side> sides = sidesValue.stream().map(eh -> Side.valueOf(eh.getValue())).
+                    collect(Collectors.toCollection(() -> EnumSet.noneOf(Side.class)));
+            final String modId = (String)ad.getAnnotationData().getOrDefault("modId", mod.getModId());
+            if (Objects.equals(mod.getModId(), modId) && sides.contains(FMLEnvironment.side)) {
+                try
+                {
+                    MinecraftForge.EVENT_BUS.register(Class.forName(ad.getClassType().getClassName(), true, loader));
+                }
+                catch (ClassNotFoundException e)
+                {
+                    LOGGER.error(LOADING, "Failed to load mod class {} for @EventBusSubscriber annotation", ad.getClassType(), e);
+                    throw new RuntimeException(e);
+                }
+            }
+        });
+    }
+
+}