Modifying(Extending,ext) portal-impl and portal-kernal Classes in Liferay 7

[Syed Ali, geändert vor 7 Jahren.]

I need to override some of the Java classes in the portal-impl and portal-kernal, is it possible in Liferay 7. how to accomplish the extending point in Liferay 7. Are there any references for overriding the Java classes such as ServicePreAction, LayoutTemplateLocalServiceImpl, TemplateProcessor in the portal-impl and portal-kernal?

[Samuel Kong, geändert vor 7 Jahren.]

You should not try to modify these classes.

For ServicePreAction, you can write your own xxxPreAction class and specify your new class in 'servlet.service.events.pre' in portal-ext.properties.

For service classes, you should write a service wrapper.

[Syed Ali, geändert vor 7 Jahren.]

Thanks Samuel,
The service wrapper reference was useful, i m trying to figure out are there any possibilities to modify the java classes i mentioned in the previous post, you mean the overriding of the java classes is not at all possible in liferay 7 or its not encouraged to override these classes?