Standard controller and extension method with same name [duplicate]

Question

Provided you have a Visualforce page that uses both a standard controller and an extension class. The extension class has a method with the same name as a method in the standard controller

(i.e, public save())

If you have the following button in your page:

<apex:commandButton value ="save" action="{!save}" />

will this call the method from the standard controller or the extension?

Answer 1

Any extension methods take precedence over controller methods with the same name. Take a look at Building a Controller Extension:

Multiple controller extensions can be defined for a single page through a comma-separated list. This allows for overrides of methods with the same name. For example, if the following page exists:

<apex:page standardController="Account"
    extensions="ExtOne,ExtTwo" showHeader="false">
    <apex:outputText value="{!foo}" />
</apex:page>

with the following extensions:

public class ExtOne {
    public ExtOne(ApexPages.StandardController acon) { }

    public String getFoo() {
        return 'foo-One';
    }
}
public class ExtTwo {
    public ExtTwo(ApexPages.StandardController acon) { }
 
    public String getFoo() {
        return 'foo-Two';
    }
}

The value of the <apex:outputText> component renders as foo-One. Overrides are defined by whichever methods are defined in the “leftmost” extension, or, the extension that is first in the comma-separated list. Thus, the getFoo method of ExtOne is overriding the method of ExtTwo.

If you have exactly one extension defined, it is "leftmost".