Ext.extend vs Ext.override?

Question

What is the difference between Ext.extend and Ext.override? In java, you extend a class and you override its methods. But looking at syntax, it seems in extjs, you can both extend a class and override a class

Answer 1

Ext.extend gives you a new class basing on existing one.

Ext.override modifies existing class without creating a new one.

It's not something specific to ExtJS. It's how JavaScript's prototype-based object model works. It's quite different from what you're used to in Java. ExtJS just adds these two utility methods to make it a bit easier to use.

Answer 2

Mchl has already answered to your query.

I just want to add, for adding features to ExtJs involves these four ways:

1. Extend
2. Override
3. Plugin
4. Sequence/Intercept

Please refer to this link for detail information:

http://www.slideshare.net/VinylFox/four-ways-to-add-features-to-ext-js