ShopPostTransactionEvent.java

package net.brcdev.shopgui.api.event;

import net.brcdev.shopgui.api.ShopTransactionResult;
import org.bukkit.event.Event;
import org.bukkit.event.HandlerList;

public class ShopPostTransactionEvent extends Event {

  private static final HandlerList handlers = new HandlerList();
  private final ShopTransactionResult result;

  public ShopPostTransactionEvent(ShopTransactionResult result) {
    this.result = result;
  }

  @Override
  public HandlerList getHandlers() {
    return handlers;
  }

  public static HandlerList getHandlerList() {
    return handlers;
  }

  public ShopTransactionResult getResult() {
    return result;
  }
}

I am sorry @brcdev, but you lack

public static HandlerList getHandlerList() {
	return handlers;
}

method, and that causes issues when I attempt to integrate your plugin.

@kangarko it's fixed now.