public class LoginEnter extends JFrame implements Runnable

private Socket connettionToServer;

ServerSocket serverSocket = new ServerSocket(1990);

    boolean returnCheakConnektion() {
        try {
            this.connettionToServer = new Socket();
            connettionToServer.connect(new InetSocketAddress("localhost",1990),300);
            return connettionToServer.isConnected();
        } catch (IOException ex) {
            return false;
        }
    }

if(returnCheakConnektion()){
                    System.out.println("Good connection to server");
                    if(returnLogin(loginField.getText().toString().trim(), passField.getText().toString().trim())){
                    accesOrdanied.setText("Accept");
                    accesOrdanied.setVisible(true);

                    exitForm();
                    }
                    else {
                        accesOrdanied.setText("Denied");
                        accesOrdanied.setVisible(true);
                    }
                }
                else{
                    accesOrdanied.setText("Sorry, but server is stoped");
                }

return connettionToServer.isConnected()

ServerSocket serverSocket = new ServerSocket(1990);