Open a link in browser with java button?

How can I open a link in default browser with a button click, along the lines of

button.addActionListener(new ActionListener() {
    public void actionPerformed(ActionEvent e) {
        open("www.google.com"); // just what is the 'open' method?
    }
});

?

Use the Desktop#browse(URI) method. It opens a URI in the user's default browser.

public static boolean openWebpage(URI uri) {
	Desktop desktop = Desktop.isDesktopSupported() ? Desktop.getDesktop() : null;
	if (desktop != null && desktop.isSupported(Desktop.Action.BROWSE)) {
		try {
			desktop.browse(uri);
            return true;
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
    return false;
}

public static boolean openWebpage(URL url) {
	try {
		return openWebpage(url.toURI());
	} catch (URISyntaxException e) {
		e.printStackTrace();
	}
    return false;
}

public static void openWebpage(String urlString) {
    try {
        Desktop.getDesktop().browse(new URL(urlString).toURI());
    } catch (Exception e) {
        e.printStackTrace();
    }
}

try {
	Desktop.getDesktop().browse(new URL("http://www.google.com").toURI());
} catch (Exception e) {}

note: you have to include necessary imports from java.net

A solution without the Desktop environment is BrowserLauncher2. This solution is more general as on Linux, Desktop is not always available.

The lenghty answer is posted at https://stackoverflow.com/a/21676290/873282

private void ButtonOpenWebActionPerformed(java.awt.event.ActionEvent evt) {                                         
    try {
        String url = "https://www.google.com";
        java.awt.Desktop.getDesktop().browse(java.net.URI.create(url));
    } catch (java.io.IOException e) {
        System.out.println(e.getMessage());
    }
}

I know that this is an old question but sometimes the Desktop.getDesktop() produces an unexpected crash like in Ubuntu 18.04. Therefore, I have to re-write my code like this:

public static void openURL(String domain)
{
    String url = "https://" + domain;
    Runtime rt = Runtime.getRuntime();
    try {
        if (MUtils.isWindows()) {
            rt.exec("rundll32 url.dll,FileProtocolHandler " + url).waitFor();
            Debug.log("Browser: " + url);
        } else if (MUtils.isMac()) {
            String[] cmd = {"open", url};
            rt.exec(cmd).waitFor();
            Debug.log("Browser: " + url);
        } else if (MUtils.isUnix()) {
            String[] cmd = {"xdg-open", url};
            rt.exec(cmd).waitFor();
            Debug.log("Browser: " + url);
        } else {
            try {
                throw new IllegalStateException();
            } catch (IllegalStateException e1) {
                MUtils.alertMessage(Lang.get("desktop.not.supported"), MainPn.getMainPn());
                e1.printStackTrace();
            }
        }
    } catch (IOException | InterruptedException e) {
        e.printStackTrace();
    }
}

public static boolean isWindows()
{
    return OS.contains("win");
}

public static boolean isMac()
{
    return OS.contains("mac");
}

public static boolean isUnix()
{
    return OS.contains("nix") || OS.contains("nux") || OS.indexOf("aix") > 0;
}

Then we can call this helper from the instance:

button.addActionListener(new ActionListener() {
    public void actionPerformed(ActionEvent e) {
        MUtils.openURL("www.google.com"); // just what is the 'open' method?
    }
});

public static void openWebPage(String url) {
    try {
        Desktop desktop = Desktop.isDesktopSupported() ? Desktop.getDesktop() : null;
        if (desktop != null && desktop.isSupported(Desktop.Action.BROWSE)) {
            desktop.browse(new URI(url));
        }
        throw new NullPointerException();
    } catch (Exception e) {
        JOptionPane.showMessageDialog(null, url, "", JOptionPane.PLAIN_MESSAGE);
    }
}