Null on register

When i want to define my Config class i get this:

Code:

[SIZE=12px][FONT=Open Sans][COLOR=#f5f5f5][15:04:10] [Server thread/WARN]: java.lang.NullPointerException[/COLOR][/FONT][/SIZE]
[SIZE=12px][FONT=Open Sans][COLOR=#f5f5f5][15:04:10] [Server thread/WARN]: at pl.diverse.opentools.Managers.Config.<init>(Config.java:19)[/COLOR][/FONT][/SIZE]
[SIZE=12px][FONT=Open Sans][COLOR=#f5f5f5][15:04:10] [Server thread/WARN]: at pl.diverse.opentools.OpenTools.load(OpenTools.java:65)[/COLOR][/FONT][/SIZE]

Line 65:

this.config = new Config(plugin);

Config, line: 19:

public File dir = this.plugin.getDataFolder();

I think its because of plugin null, but plugin is defined by:

protected static OpenTools plugin;

public void onEnable() {
plugin = this;
load();
registerCommands();
registerEvents();
scheduler();
}

 

DevManABCD Why protected?

 

Don't refer to "this" or any of the object outside of object methods and constructors.