Java:opening a folder in windows explorer

Opening a directory from Java on Windows with the start command

String cmd = "cmd.exe /c start ";
String file = "c:\\";
Runtime.getRuntime().exec(cmd + file);

In this quick tip, I’m going to show you how to pop open Windows Explorer directly from your Java application. The snippet above constructs a command that tells cmd.exe to run the built‑in start utility. When start receives a folder path, Windows opens Explorer instead of a console window—exactly what we want.

How it works step by step:

• The cmd.exe /c prefix runs a command and then terminates the command prompt.
• start launches a new process in a separate window; for directories, this means Explorer.
• Runtime.getRuntime().exec(…) hands the assembled string to the operating system.

One thing to keep in mind: if the directory path contains spaces, you must wrap it in escaped quotes. For example:

String file = "\"C:\\Program Files\"";
Runtime.getRuntime().exec("cmd.exe /c start " + file);

Alternatives: Starting with Java 6 you can use the Desktop API:

Desktop.getDesktop().open(new File("C:\\"));

That approach is more portable, but it may fail on headless systems or if the file isn’t a directory. For Windows‑specific utilities the start trick is reliable and gives you full control.

If you need to capture output or handle errors more gracefully, switch to ProcessBuilder. As an example:

ProcessBuilder pb = new ProcessBuilder("cmd.exe", "/c", "start", "C:\\");
pb.start();

Testing…