Aura.cmp

<aura:component extends="force:slds" controller="SubClass">
    <aura:attribute name="accounts" type="Account[]"/>
    <aura:handler name="init" value="{!this}" action="{!c.init}" />
    <ul>
        <aura:iteration items="{!v.accounts}" var="account">
              <li>{!account.Name} ({!account.Id})</li>
        </aura:iteration>
    </ul>
</aura:component>

AuraController.js

({
    init : function(component, event, helper) {
        helper.getAccounts(component);
    }
})

AuraHelper.js

({
    getAccounts : function(component) {
        let action = component.get("c.getAccounts");
        action.setCallback(this, function(response) {
            if (response.getState() == "SUCCESS") {
                component.set("v.accounts", response.getReturnValue());
            }
        });
        $A.enqueueAction(action);
    }
})

SubClass.cls

public with sharing class SubClass extends SuperClass {
}

SuperClass.cls

public with sharing abstract class SuperClass {
    @AuraEnabled
    public static List<Account> getAccounts() {
        List<Account> accounts = [SELECT Id, Name FROM Account ORDER BY Name asc];
        return accounts;
    }
}