Determine if running on a rooted device

My app has a certain piece of functionality that will only work on a device where root is available. Rather than having this feature fail when it is used (and then show an appropriate error message to the user), I'd prefer an ability to silently check if root is available first, and if not,hide the respective options in the first place.

Is there a way to do this?

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Here is a class that will check for Root one of three ways.

/** @author Kevin Kowalewski */
public class RootUtil {
    public static boolean isDeviceRooted() {
        return checkRootMethod1() || checkRootMethod2() || checkRootMethod3();
    }

    private static boolean checkRootMethod1() {
        String buildTags = android.os.Build.TAGS;
        return buildTags != null && buildTags.contains("test-keys");
    }

    private static boolean checkRootMethod2() {
        String[] paths = { "/system/app/Superuser.apk", "/sbin/su", "/system/bin/su", "/system/xbin/su", "/data/local/xbin/su", "/data/local/bin/su", "/system/sd/xbin/su",
                "/system/bin/failsafe/su", "/data/local/su", "/su/bin/su"};
        for (String path : paths) {
            if (new File(path).exists()) return true;
        }
        return false;
    }

    private static boolean checkRootMethod3() {
        Process process = null;
        try {
            process = Runtime.getRuntime().exec(new String[] { "/system/xbin/which", "su" });
            BufferedReader in = new BufferedReader(new InputStreamReader(process.getInputStream()));
            if (in.readLine() != null) return true;
            return false;
        } catch (Throwable t) {
            return false;
        } finally {
            if (process != null) process.destroy();
        }
    }
}