# Green NullPointerExeption

**URL:** <https://discourse.processing.org/t/green-nullpointerexeption/19377>\
**Category:** Libraries\
**Created:** [April 4, 2020, 2:14am UTC](https://discourse.processing.org/t/green-nullpointerexeption/19377 "2020-04-04T02:14:49Z")\
**Posts on this page:** 9\
**Page:** 1

<div class="post-metadata">

**Author:** ![Odermonicon](https://avatars.discourse-cdn.com/v4/letter/o/96bed5/32.png) [@Odermonicon](https://discourse.processing.org/u/Odermonicon)\
**Post date:** [April 4, 2020, 2:14am UTC](https://discourse.processing.org/t/green-nullpointerexeption/19377/1 "2020-04-04T02:14:49Z")

</div>

> **MCVE**
>
> ```auto
> import Green.*;
> class ExampleActor extends Actor
> {
> public ExampleActor(float x, float y, int w, int h)
> {
> super(x, y, w, h); // Line causing error
> }
> public void act(float deltaTime)
> {
> }
> }
> ExampleActor atr = new ExampleActor(1,1,1,1);
> 
> ```

Why does this trigger a nullpointer exeption?

---

<div class="post-metadata">

**Author:** ![SomeOne](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.processing.org/someone/32/8639_2.png) [@SomeOne](https://discourse.processing.org/u/SomeOne)\
**Post date:** [April 4, 2020, 3:23am UTC](https://discourse.processing.org/t/green-nullpointerexeption/19377/2 "2020-04-04T03:23:28Z")

</div>

This is a pure guess, based on very limited information, but giving values 1,1,1,1 to constructor could break it. It might break some initialization, so try other values especially larger w(idth) and h(eight) values.

---

<div class="post-metadata">

**Author:** ![Odermonicon](https://avatars.discourse-cdn.com/v4/letter/o/96bed5/32.png) [@Odermonicon](https://discourse.processing.org/u/Odermonicon)\
**Post date:** [April 4, 2020, 3:24am UTC](https://discourse.processing.org/t/green-nullpointerexeption/19377/3 "2020-04-04T03:24:51Z")

</div>

just tried 100,100,100,100 (it didn’t work.) it’s even weirder.

---

<div class="post-metadata">

**Author:** ![SomeOne](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.processing.org/someone/32/8639_2.png) [@SomeOne](https://discourse.processing.org/u/SomeOne)\
**Post date:** [April 4, 2020, 3:26am UTC](https://discourse.processing.org/t/green-nullpointerexeption/19377/4 "2020-04-04T03:26:50Z")

</div>

what if x,y and w and h have different value, like (10,10,30,30)?

---

<div class="post-metadata">

**Author:** ![Odermonicon](https://avatars.discourse-cdn.com/v4/letter/o/96bed5/32.png) [@Odermonicon](https://discourse.processing.org/u/Odermonicon)\
**Post date:** [April 4, 2020, 3:28am UTC](https://discourse.processing.org/t/green-nullpointerexeption/19377/5 "2020-04-04T03:28:20Z")

</div>

just tried 10,20,30,40. nope!

---

<div class="post-metadata">

**Author:** ![SomeOne](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.processing.org/someone/32/8639_2.png) [@SomeOne](https://discourse.processing.org/u/SomeOne)\
**Post date:** [April 4, 2020, 3:29am UTC](https://discourse.processing.org/t/green-nullpointerexeption/19377/6 "2020-04-04T03:29:27Z")

</div>

What does documentation tell you?

---

<div class="post-metadata">

**Author:** ![Odermonicon](https://avatars.discourse-cdn.com/v4/letter/o/96bed5/32.png) [@Odermonicon](https://discourse.processing.org/u/Odermonicon)\
**Post date:** [April 4, 2020, 3:30am UTC](https://discourse.processing.org/t/green-nullpointerexeption/19377/7 "2020-04-04T03:30:40Z")

</div>

> Constructor and Description  
> `Actor(float x, float y, int w, int h)`
> 
> Creates the new actor at a position with a defined width and height.

from [Actor (Javadocs: Green)](https://zedseven.github.io/Green/Green/Actor.html)

---

<div class="post-metadata">

**Author:** ![SomeOne](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.processing.org/someone/32/8639_2.png) [@SomeOne](https://discourse.processing.org/u/SomeOne)\
**Post date:** [April 4, 2020, 3:45am UTC](https://discourse.processing.org/t/green-nullpointerexeption/19377/8 "2020-04-04T03:45:46Z")

</div>

Something else is missing then. Perhaps you need to create world object first for actor to reside in?

```auto
public abstract class World
extends java.lang.Object

The base class for all worlds in the library. A world is it's own area for a collection of Actor instances to interact in, though any given Actor can be within multiple worlds at a time. Only one world may be active at a time however, which can be changed by calling Green.loadWorld(World).

```

---

<div class="post-metadata">

**Author:** ![Odermonicon](https://avatars.discourse-cdn.com/v4/letter/o/96bed5/32.png) [@Odermonicon](https://discourse.processing.org/u/Odermonicon)\
**Post date:** [April 4, 2020, 4:14am UTC](https://discourse.processing.org/t/green-nullpointerexeption/19377/9 "2020-04-04T04:14:32Z")

</div>

as i feared, it gets an error while creating the world.

```auto
import Green.*;
class ExampleActor extends World
{
  public ExampleActor()
  {
    super(); // Line causing error
  }
  public void act(float deltaTime)
  {
  }
  public void prepare()
  {
  }
}
ExampleActor atr = new ExampleActor();

```

UPDATE: wait, `new ExampleActor();` causes the error? i got rid of it and it worked flawlessly!