Detect if Java application was run as a Windows admin

I’ve found a different solution that seems to be platform-independent. It tries to write system-preferences. If that fails, the user might not be an admin.

As Tomáš Zato suggested, you might want to suppress error messages caused by this method. You can do this by setting System.err:

import java.io.OutputStream;
import java.io.PrintStream;
import java.util.prefs.Preferences;

import static java.lang.System.setErr;
import static java.util.prefs.Preferences.systemRoot;

public class AdministratorChecker
{
    public static final boolean IS_RUNNING_AS_ADMINISTRATOR;

    static
    {
        IS_RUNNING_AS_ADMINISTRATOR = isRunningAsAdministrator();
    }

    private static boolean isRunningAsAdministrator()
    {
        Preferences preferences = systemRoot();

        synchronized (System.err)
        {
            setErr(new PrintStream(new OutputStream()
            {
                @Override
                public void write(int b)
                {
                }
            }));

            try
            {
                preferences.put("foo", "bar"); // SecurityException on Windows
                preferences.remove("foo");
                preferences.flush(); // BackingStoreException on Linux
                return true;
            } catch (Exception exception)
            {
                return false;
            } finally
            {
                setErr(System.err);
            }
        }
    }
}