How to get list of Entity that can summon

First, please excuse my spelling errors.

I need to get the list of the entities that can summon by the commands. I've tried EntityList#getEntityNameList and EntityList#getClass , but as I'm using this, game crashed because of the Entity that spawned.

Please tell me how to do, thanks.

package task.heartstone.register;

import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import java.util.Set;

import org.apache.logging.log4j.LogManager;

import net.minecraft.entity.Entity;
import net.minecraft.entity.EntityList;
import net.minecraft.entity.passive.EntityPig;
import net.minecraft.util.ResourceLocation;
import net.minecraft.world.World;

public class EntityUtil {
	
	public static final List<Class<? extends Entity>> list = new ArrayList<Class<? extends Entity>>();
	
	public static void load() {
		Set<ResourceLocation> namelist = EntityList.getEntityNameList();
		for(ResourceLocation name : namelist) {
			Class<? extends Entity> clazz = EntityList.getClass(name);
			if(clazz != null) {
				list.add(clazz);
			}
		}
		for(Class clazz : list) {
			LogManager.getLogger("EntityUtil").info(clazz.getName());
		}
	}
	
	public static Entity getRandEntity(World world) {
		Random rand = new Random();
		int index = rand.nextInt(list.size()-1);
		return EntityList.newEntity(list.get(index), world);
	}
	
}