Is there a way to get a dedicated server instance? I need it for some entity manipulation in my GUI. This code works fine on the client:

FMLCommonHandler.instance().getMinecraftServerInstance()

 

but on a dedicated server, it gives me a null value. Here's my CommonProxy:

 

package SanAndreasP.mods.ClaySoldiersMod;

import java.util.ArrayList;
import java.util.List;

import net.minecraft.client.Minecraft;
import net.minecraft.server.MinecraftServer;
import net.minecraft.src.*;

import cpw.mods.fml.common.FMLCommonHandler;
import cpw.mods.fml.common.network.IGuiHandler;
import cpw.mods.fml.common.registry.GameRegistry;

public class CSM_CommonProxy implements IGuiHandler {

@Override
public Object getServerGuiElement(int ID, EntityPlayer player, World world, int x, int y, int z) {
	List<Entity> entities = world.getEntitiesWithinAABB(CSM_EntityClayNexus.class, AxisAlignedBB.getBoundingBox(x, y, z, x+1D, y+1D, z+1D));

	for(Entity entity : entities) {
		if (entity != null && entity instanceof CSM_EntityClayNexus) {
			return new CSM_ContainerNexus(player.inventory, (CSM_EntityClayNexus)entity, ID == 0);
		} else {
			return null;
		}
	}

	return null;
}

@Override
public Object getClientGuiElement(int ID, EntityPlayer player, World world, int x, int y, int z) {

	List<Entity> entitiesC = world.getEntitiesWithinAABB(CSM_EntityClayNexus.class, AxisAlignedBB.getBoundingBox(x, y, z, x+1D, y+1D, z+1D));
	List<Entity> entitiesS = new ArrayList<Entity>();
	System.out.println();

	try {
		entitiesS = FMLCommonHandler.instance().getMinecraftServerInstance().worldServerForDimension(0).getEntitiesWithinAABB(CSM_EntityClayNexus.class, AxisAlignedBB.getBoundingBox(x, y, z, x+1D, y+1D, z+1D));
	} catch (NullPointerException e) {

	}



	CSM_EntityClayNexus clientEntity = null, serverEntity = null;

	for(Entity entity : entitiesS) {
		if(entity != null && entity instanceof CSM_EntityClayNexus) {
			serverEntity = (CSM_EntityClayNexus)entity;
			break;
		}
	}
	for(Entity entity : entitiesC) {
		if(entity != null && entity instanceof CSM_EntityClayNexus) {
			clientEntity = (CSM_EntityClayNexus)entity;
			break;
		}
	}

	if(clientEntity != null && serverEntity != null) {
		System.out.println(ID);
		return new CSM_GuiNexus(player, clientEntity, serverEntity, ID == 0);
	} else if(clientEntity != null) {
		System.out.println(ID);
		return new CSM_GuiNexus(player, clientEntity, clientEntity, ID == 0);
	} else {
		return null;
	}
}

public boolean isClient() {
	return false;
}

public void registerRenderInformation() { }

public void showEffect(String effect, Object... data) { }

}

 

Try the modsloader one, or use a variable that gets initialized @ServerStartup, I use the variable style, I found it works better and it looks cleaner, but that is opinion.