title: No visible @interface declares the selector error
body: <p>I have a connection class in my project. I want to use this class in for a lot of works. When I tried to call this class's function getting following error  : No visible @interface declares the selector error</p>
  
  <p>coreConnection.h </p>
  
  <pre><code>@interface coreConnection:NSArray
  {
      NSData *returnData;
  }
        -(NSArray*)getData;
  @end
  </code></pre>
  
  <p>coreConnection.m</p>
  
  <pre><code>#import "coreConnection.h"
  
  @implementation coreConnection
  
  -(NSArray*)getData:(NSString*)link
  {
      NSOperationQueue *apiCallsQueue = [[NSOperationQueue alloc] init];
      NSURL *URL = [NSURL URLWithString:link];
      NSURLRequest *request = [NSURLRequest requestWithURL:URL];
      [NSURLConnection sendAsynchronousRequest:request queue:apiCallsQueue completionHandler:^(NSURLResponse *response, NSData *data, NSError *error) {
          dispatch_async(dispatch_get_main_queue(), ^{
              returnData = data;
          });
      }];
      return [NSJSONSerialization JSONObjectWithData:returnData options:nil error:nil];
  }
  @end
  </code></pre>
  
  <p>viewController.m</p>
  
  <pre><code>#import "coreConnection.h"
  
  - (void)viewDidLoad
  {
      [[self headlineCollectionView]setDelegate:self];
      [[self headlineCollectionView]setDataSource:self];
       [self.headlineCollectionView registerNib:[UINib nibWithNibName:@"HeadLineCell" bundle:nil] forCellWithReuseIdentifier:@"CELL"];
      coreConnection speed=[[coreConnection alloc] init];;
      headline = [speed getData:@"string"];
      [self.headlineCollectionView reloadData];
  [super viewDidLoad];
  }
  </code></pre>