try {
String command;
String os = System.getProperty("os.name").toLowerCase();
if (os.contains("linux") || os.contains("mac os x"))
command = "shutdown -h now";
else if (os.contains("windows"))
command = "shutdown /p";
else
throw new Exception("Unsupported operating system.");
Runtime.getRuntime().exec(command);
System.exit(0);
} catch (Exception ex) {
JOptionPane.showMessageDialog(null, ex.getMessage());
}
For Linux and Mac OS X, the command for immediate shutdown is shutdown -h now. But in Windows, it is shutdown /p. The above java code checks the operating system. Then it assumes appropriate shutdown command and then executes it. This java code can shutdown a computer.