# Update()

> Executes the system immediately.

## Definition

* **Type:** Method
* **Namespace:** [Unity.Entities](/engine/7000.0/script-reference/unity/entities.md)
* **Assembly:** UnityEngine.EntitiesModule

```csharp
public abstract void Update()
```

### Remarks

The exact behavior is determined by this system's specific subclass.

Additional Resources: [SystemBase](/engine/7000.0/script-reference/unity/entities/systembase.md), [ComponentSystemGroup](/engine/7000.0/script-reference/unity/entities/componentsystemgroup.md), [EntityCommandBufferSystem](/engine/7000.0/script-reference/unity/entities/entitycommandbuffersystem.md)