Can't access swift class from Objective-C while the project is in Swift

Question

I have a swift project and my initial UIViewController is a swift class.

From the initial ViewController, I added a new Viewcontroller in my storyboard and set an objective-c class (FirstViewController.h) for it.

In my project, I have another swift class (DataManager.Swift) which is a subclass of NSObject.

Now I want to create an instance of this DataManager.swift in my objective-C class (FirstViewController.m). But unfortunately, i couldn't create this instance, giving me an error like - Receiver 'DataManager' for class message is a forward declaration

What can I do now to resolve this issue? Is it possible to access swift class from Objectibe-C class while project is in swift?

My FirstViewController.m,

#import "FirstViewController.h"
@class DataManager;

@interface FirstViewController ()

@property (nonatomic, strong) DataManager *dataManager;

@end

@implementation FirstViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view.
   _dataManager = [[DataManager alloc] init]; //This line giving me that error
}
@end

My DataManager.swift class,

import UIKit;

@objc class DataManager: NSObject {
    var a: Int = 0
}

My BridgingHeaderFile,

#ifndef BridgingHeader_h
#define BridgingHeader_h
#import "FirstViewController.h"
#endif

Answer 1

You should import your swift module into your .m file with this syntax:
#import "ModuleName-Swift.h" where ModuleName usually is your Project Name.
NOTE: adding -Swift suffix is important!

Also @class DataManager; will be redundant after import.