Replace abstract class with class and a private constructor to prevent instantiation of a class.

src/main/java/com/yes/yes/utils/EntityRegistry.java

@@ -5,7 +5,10 @@ import com.yes.yes.utils.exceptions.AlreadyExistsException;
 import java.util.ArrayList;
 import java.util.HashMap;
 
-public abstract class EntityRegistry {
+public class EntityRegistry {
+    private EntityRegistry() {
+    }
+
     private static final HashMap<String, RegistryEntry> entities = new HashMap<>();
 
     public static void register(RegistryEntry entry) throws AlreadyExistsException {

src/main/java/com/yes/yes/utils/GlobalEventHandler.java

@@ -3,7 +3,10 @@ package com.yes.yes.utils;
 import java.util.function.Consumer;
 import java.util.function.Function;
 
-public abstract class GlobalEventHandler {
+public class GlobalEventHandler {
+    private GlobalEventHandler() {
+    }
+
     private static final EventHandler handler = new EventHandler();
 
     public static <T> void addListener(String eventName, Consumer<T> function) {