src/main/java/net/fabricmc/example/ExampleMod.java

@@ -2,7 +2,7 @@ package net.fabricmc.example;
 
 import net.fabricmc.api.ModInitializer;
 
-public class ExampleMod implements ModInitializer, ClientModInitializer {
+public class ExampleMod implements ModInitializer {
 	@Override
 	public void onInitialize() {
 		// This code runs as soon as Minecraft is in a mod-load-ready state.
@@ -11,13 +11,4 @@ public class ExampleMod implements ModInitializer, ClientModInitializer {
 
 		System.out.println("Hello Fabric world!");
 	}
-	
-	@Override
-	public void onInitializeClient() {
-		// This code runs on the client side only, and should be used to set up
-		// client-side logic, such as render or integrated-server tweaks.
-		// Proceed with mild caution.
-		
-		System.out.println("Hello client world!");
-	}
 }

src/main/java/net/fabricmc/example/client/ExampleClientMod.java

@@ -0,0 +1,14 @@
+package net.fabricmc.example.client;
+
+import net.fabricmc.api.ClientModInitializer;
+
+public class ExampleClientMod implements ClientModInitializer {
+	@Override
+	public void onInitializeClient() {
+		// This code runs on the client side only, and should be used to set up
+		// client-side logic, such as render or integrated-server tweaks.
+		// Proceed with mild caution.
+
+		System.out.println("Hello client world!");
+	}
+}

src/main/resources/fabric.mod.json

@@ -22,7 +22,7 @@
       "net.fabricmc.example.ExampleMod"
     ],
     "client": [
-      "net.fabricmc.example.ExampleMod"
+      "net.fabricmc.example.client.ExampleClientMod"
     ]
   },
   "mixins": [