[swift-users] Is this valid Swift 3 (and later) code?

[Ethin Probst]

Is the following code valid swift 3 (and later) code? If not, is it
translatable to swift 3? This was translated using Elements Oxidizer
(http://elementscompiler.com/elements/oxidizer.aspx) using the Hello
World Java Swing application
(https://docs.oracle.com/javase/tutorial/displayCode.html?code=https://docs.oracle.com/javase/tutorial/uiswing/examples/start/HelloWorldSwingProject/src/start/HelloWorldSwing.java
and https://docs.oracle.com/javase/tutorial/uiswing/examples/start/HelloWorldSwingProject/src/start/HelloWorldSwing.java).
It will run in RemObjects Silver in Visual Studio, but is it valid
Swift 3 code? You don't have to try and compile it--as Elements is the
only platform that compiles Swift to the JVM (I think?) but does it
follow the Swift 3 language specification (or the latest version,
whatever that may be)?
Code:
[start code]
import javax.swing

public class HelloWorldSwing {
	private static func createAndShowGUI() {
		//Create and set up the window.
		var frame: JFrame! = JFrame("HelloWorldSwing")
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE)
		//Add the ubiquitous "Hello World" label.
		var label: JLabel! = JLabel("Hello World")
		frame.getContentPane().add(label)
		//Display the window.
		frame.pack()
		frame.setVisible(true)
	}

	public static func main(_ args: String![]) {
		//Schedule a job for the event-dispatching thread:
		//creating and showing this application's GUI.
		javax.swing.SwingUtilities.invokeLater(class Runnable {
			func run() {
				createAndShowGUI()
			}
		})
	}
}
[end code]
-- 
Signed,
Ethin D. Probst