4. Advanced Features

4.1. Assertions and Contract Programming

4.2. Error Handling

4.3. Parameter Directions

4.4. Collections

• 4.4.1. ArrayList<G>
• 4.4.2. HashMap<K,V>
• 4.4.3. HashSet<G>
• 4.4.4. Read-Only Views

4.5. Methods with Syntax Support

4.6. Multi-Threading

• 4.6.1. Threads in Vala
• 4.6.2. Resource Control

4.7. The Main Loop

4.8. Asynchronous Methods

• 4.8.1. Examples

4.9. Weak References

4.10. Ownership

• 4.10.1. Unowned References
• 4.10.2. Methods ownership
• 4.10.3. Properties ownership
• 4.10.4. Ownership Transfer

4.11. Variable Length Argument Lists

4.12. Pointers

4.13. Non-Object Classes

4.14. D-Bus Integration

4.15. Profiles