public static boolean CopyAssetsFile(Context context,String assetFile, String outFile) throws Exception {
        FileOutputStream fo = new FileOutputStream(outFile);
        InputStream assetsDB = context.getAssets().open(assetFile);
        byte[] buffer = new byte[512];
        int length;
        while ((length = assetsDB.read(buffer)) > 0) {
            fo.write(buffer, 0, length);
        }
        fo.flush();
        fo.close();
        assetsDB.close();
        return true;
    }

    try {
            String apkName = "test.apk";
            String apkDir = "/data/data/com.xxx.demo/apps";
            File apkDirPath = new File(apkDir);
            if (!apkDirPath.exists()) {
                apkDirPath.mkdir();
            }
            String apkUrl = apkDir + "/" + apkName;
            File apkFile = new File(apkUrl);
            if (apkFile.exists()) {
                apkFile.delete();
            }
            CopyAssetsFile(this, apkName, apkUrl);
        } catch (Exception ex) {
            Log.e("Error", ex.getMessage());
        }