 import net.minecraft.client.network.NetworkPlayerInfo;
 import net.minecraft.client.renderer.ThreadDownloadImageData;
 import net.minecraft.util.ResourceLocation;
import net.minecraftforge.fml.common.ObfuscationReflectionHelper;
import net.minecraftforge.fml.relauncher.ReflectionHelper;
 
 import java.lang.reflect.Field;
 import java.net.URL;
 
 /**
  * Default Cape implementation
- * 
+ *
  * @author jadar
  */
 public class StaticCape extends AbstractCape {
 @@ -41,16 +43,17 @@ public void loadTexture(AbstractClientPlayer player) {
 
         //mmdanggg2: using reflection to modify the private locationCape, hacky but it works.
         try {
            Field playerInfoF = AbstractClientPlayer.class.getDeclaredField("playerInfo");
        	Field playerInfoF = ReflectionHelper.findField(AbstractClientPlayer.class, "playerInfo", "field_175157_a");
             playerInfoF.setAccessible(true);
             NetworkPlayerInfo nci = (NetworkPlayerInfo) playerInfoF.get(player);
 
           Field locationCapeF = NetworkPlayerInfo.class.getDeclaredField("locationCape");
           Field locationCapeF = ReflectionHelper.findField(NetworkPlayerInfo.class, "locationCape", "field_178862_f");
             locationCapeF.setAccessible(true);
             locationCapeF.set(nci, location);
 
             playerInfoF.setAccessible(false);
             locationCapeF.setAccessible(false);

         } catch (Exception e) {
             e.printStackTrace();
             DevCapes.getInstance().logger.error("Setting cape ResourceLocation failed!");

/**
 * DeveloperCapes by Jadar
 * License: MIT License
 * (https://raw.github.com/jadar/DeveloperCapes/master/LICENSE)
 * version 4.0.0.x
 */
package com.jadarstudios.developercapes.cape;

import com.jadarstudios.developercapes.DevCapes;
import com.jadarstudios.developercapes.HDImageBuffer;
import com.mojang.authlib.minecraft.MinecraftProfileTexture;

import net.minecraft.client.Minecraft;
import net.minecraft.client.entity.AbstractClientPlayer;
import net.minecraft.client.network.NetworkPlayerInfo;
import net.minecraft.client.renderer.ThreadDownloadImageData;
import net.minecraft.util.ResourceLocation;
import net.minecraftforge.fml.common.ObfuscationReflectionHelper;
import net.minecraftforge.fml.relauncher.ReflectionHelper;

import java.lang.reflect.Field;
import java.net.URL;

/**
 * Default Cape implementation
 *
 * @author jadar
 */
public class StaticCape extends AbstractCape {

    public StaticCape(String name, URL url) {
        this.setName(name);
        this.setURL(url);
    }

    public StaticCape(String name) {
        this(name, null);
    }

    @Override
    public void loadTexture(AbstractClientPlayer player) {
        ResourceLocation location = this.getLocation();

        //mmdanggg2: using reflection to modify the private locationCape, hacky but it works.
        try {
        	Field playerInfoF = ReflectionHelper.findField(AbstractClientPlayer.class, "playerInfo", "field_175157_a");
            playerInfoF.setAccessible(true);
            NetworkPlayerInfo nci = (NetworkPlayerInfo) playerInfoF.get(player);

            Field locationCapeF = ReflectionHelper.findField(NetworkPlayerInfo.class, "locationCape", "field_178862_f");
            locationCapeF.setAccessible(true);
            locationCapeF.set(nci, location);

            playerInfoF.setAccessible(false);
            locationCapeF.setAccessible(false);

        } catch (Exception e) {
            e.printStackTrace();
            DevCapes.getInstance().logger.error("Setting cape ResourceLocation failed!");
        }

        Minecraft.getMinecraft().renderEngine.loadTexture(location, this.getTexture());
    }

    @Override
    public boolean isTextureLoaded(AbstractClientPlayer player) {
        ResourceLocation cape = player.getLocationCape();
        return cape != null;
    }

    public void setURL(URL url) {
        if (url == null) {
            this.texture = null;
            return;
        }
        this.texture = new ThreadDownloadImageData(null, url.toString(), null, new HDImageBuffer());
    }

    public void setName(String name) {
        this.name = name;
        this.location = new ResourceLocation("DevCapes/" + name);
    }
}

Update StaticCape.java