SkullUtil.java

import com.mojang.authlib.GameProfile;
import com.mojang.authlib.properties.Property;
import org.bukkit.Bukkit;
import org.bukkit.Material;
import org.bukkit.inventory.ItemStack;
import org.bukkit.inventory.meta.ItemMeta;
import org.jetbrains.annotations.NotNull;

import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.UUID;

/**
 * An utility class to get skulls with specified base64 texture set.
 */
@SuppressWarnings({"CallToPrintStackTrace", "deprecation"})
public final class SkullUtil {

    private static Method setProfileMethod;
    private static Field profileField;
    private static boolean ran;

    public static @NotNull ItemStack getSkull(final @NotNull String base64, final int amount) {
        final ItemStack item = new ItemStack(Material.PLAYER_HEAD, amount, (short) 3);
        final ItemMeta meta = item.getItemMeta();

        if (!ran) {
            final Class<? extends ItemMeta> clazz = meta.getClass();

            try {
                setProfileMethod = clazz.getDeclaredMethod("setProfile", GameProfile.class);
                setProfileMethod.setAccessible(true);
            } catch (final NoSuchMethodException ignored) {
                // introduced in 1.15.1, can be ignored safely
            }

            try {
                profileField = clazz.getDeclaredField("profile");
                profileField.setAccessible(true);
            } catch (final NoSuchFieldException e) {
                e.printStackTrace();
            }

            ran = true;
        }

        final GameProfile profile = new GameProfile(UUID.randomUUID(), "");
        profile.getProperties().put("textures", new Property("textures", base64));

        setProfileLabel:
        {
            if (setProfileMethod != null) {
                try {
                    setProfileMethod.invoke(meta, profile);
                    break setProfileLabel;
                } catch (final IllegalAccessException | InvocationTargetException e) {
                    e.printStackTrace();
                }
            }

            if (profileField != null) {
                try {
                    profileField.set(meta, profile);
                    break setProfileLabel;
                } catch (final IllegalAccessException e) {
                    e.printStackTrace();
                }
            }

            final IllegalStateException e = new IllegalStateException("could not set profile for player head, server version: " + Bukkit.getBukkitVersion());
            e.printStackTrace();
        }

        item.setItemMeta(meta);
        return item;
    }
}