checkAndDeleteBackupFile() method is used to delete the oldest backup file and keep the count of file to maximum of MAXIMUM_DATABASE_FILE

checkAndDeleteBackupFile.java

public static void checkAndDeleteBackupFile(File directory, String path) {
        //This is to prevent deleting extra file being deleted which is mentioned in previous comment lines.
        File currentDateFile = new File(path);
        int fileIndex = -1;
        long lastModifiedTime = System.currentTimeMillis();

        if (!currentDateFile.exists()) {
            File[] files = directory.listFiles();
            if (files != null && files.length >= MAXIMUM_DATABASE_FILE) {
                for (int i = 0; i < files.length; i++) {
                    File file = files[i];
                    long fileLastModifiedTime = file.lastModified();
                    if (fileLastModifiedTime < lastModifiedTime) {
                        lastModifiedTime = fileLastModifiedTime;
                        fileIndex = i;
                    }
                }

                if (fileIndex != -1) {
                    File deletingFile = files[fileIndex];
                    if (deletingFile.exists()) {
                        deletingFile.delete();
                    }
                }
            }
        }
    }