How do I open the default mail program with a Subject and Body in a cross-platform way?

Question

How do I open the default mail program with a Subject and Body in a cross-platform way?

Unfortunately, this is for a a client app written in Java, not a website.

I would like this to work in a cross-platform way (which means Windows and Mac, sorry Linux). I am happy to execute a VBScript in Windows, or AppleScript in OS X. But I have no idea what those scripts should contain. I would love to execute the user's default program vs. just searching for Outlook or whatever.

In OS X, I have tried executing the command:

open mailto:?subject=MySubject&body=TheBody

URL escaping is needed to replace spaces with %20.

Updated On Windows, you have to play all sorts of games to get start to run correctly. Here is the proper Java incantation:

class Win32 extends OS {
    public void email(String subject, String body) throws Exception {
        String cmd = "cmd.exe /c start \"\" \"" + formatMailto(subject, body) + "\"";
        Runtime.getRuntime().exec(cmd);
    }
}

Answer 1

Never use Runtime.exec(String) on Mac OS X or any other operating system. If you do that, you'll have to figure out how to properly quote all argument strings and so on; it's a pain and very error-prone.

Instead, use Runtime.exec(String[]) which takes an array of already-separated arguments. This is much more appropriate for virtually all uses.