How i can get the Application Menu in Cocoa

Without IB, you can access the menu using the NSApplication's mainMenu:

NSMenu *mainMenu = [[NSApplication sharedApplication] mainMenu];
NSMenu *appMenu = [[mainMenu itemAtIndex:0] submenu];

for (NSMenuItem *item in [appMenu itemArray]) {
    NSLog(@"%@", [item title]);
}

Though this is 5 years old question... I like to share how to make it.

In my experience in OS X 10.11 (El Capitan) with Xcode 7.1, it's not hard to replicate that application menu. It seems Apple removed all the weird limitations.

Note: This code is updated for Swift 3, and tested only in macOS Sierra (10.12.1).

//
//  AppDelegate.swift
//  Editor6MainMenuUI2Testdrive
//
//  Created by Hoon H. on 2016/11/05.
//  Copyright © 2016 Eonil. All rights reserved.
//

import Cocoa

/// You SHOULD NOT use `@NSApplicationMain` 
/// to make your custom menu to work.
class AppDelegate: NSObject, NSApplicationDelegate {
    func applicationDidFinishLaunching(_ aNotification: Notification) {}
    func applicationWillTerminate(_ aNotification: Notification) {}
}

func makeMainMenu() -> NSMenu {
    let mainMenu            = NSMenu() // `title` really doesn't matter.
    let mainAppMenuItem     = NSMenuItem(title: "Application", action: nil, keyEquivalent: "") // `title` really doesn't matter.
    let mainFileMenuItem    = NSMenuItem(title: "File", action: nil, keyEquivalent: "")
    mainMenu.addItem(mainAppMenuItem)
    mainMenu.addItem(mainFileMenuItem)

    let appMenu             = NSMenu() // `title` really doesn't matter.
    mainAppMenuItem.submenu = appMenu

    let appServicesMenu     = NSMenu()
    NSApp.servicesMenu      = appServicesMenu

    appMenu.addItem(withTitle: "About Me", action: nil, keyEquivalent: "")
    appMenu.addItem(NSMenuItem.separator())
    appMenu.addItem(withTitle: "Preferences...", action: nil, keyEquivalent: ",")
    appMenu.addItem(NSMenuItem.separator())
    appMenu.addItem(withTitle: "Hide Me", action: #selector(NSApplication.hide(_:)), keyEquivalent: "h")
    appMenu.addItem({ () -> NSMenuItem in
        let m = NSMenuItem(title: "Hide Others", action: #selector(NSApplication.hideOtherApplications(_:)), keyEquivalent: "h")
        m.keyEquivalentModifierMask = [.command, .option]
        return m
        }())
    appMenu.addItem(withTitle: "Show All", action: #selector(NSApplication.unhideAllApplications(_:)), keyEquivalent: "")

    appMenu.addItem(NSMenuItem.separator())
    appMenu.addItem(withTitle: "Services", action: nil, keyEquivalent: "").submenu = appServicesMenu
    appMenu.addItem(NSMenuItem.separator())
    appMenu.addItem(withTitle: "Quit Me", action: #selector(NSApplication.terminate(_:)), keyEquivalent: "q")

    let fileMenu = NSMenu(title: "File")
    mainFileMenuItem.submenu = fileMenu
    fileMenu.addItem(withTitle: "New...", action: #selector(NSDocumentController.newDocument(_:)), keyEquivalent: "n")

    return mainMenu
}

let del = AppDelegate()
/// Setting main menu MUST be done before you setting app delegate.
/// I don't know why.
NSApplication.shared().mainMenu = makeMainMenu()
NSApplication.shared().delegate = del
NSApplication.shared().run()

Anyway, it is not being generated automatically, and I had to set them all up myself. I am not sure whether there is another way to do this or not.

You can download working example here.