code: private void checkParams()
     {
        if (backupDir == null)
        {
           throw new IllegalStateException(BACKUP_DIR + " not specified");
        }
  
        logsDirectory = new File(backupDir);
        if (!PrivilegedFileHelper.exists(logsDirectory))
        {
           if (!PrivilegedFileHelper.mkdirs(logsDirectory))
           {
              throw new IllegalStateException("Could not create the backup directory at "
                 + logsDirectory.getAbsolutePath());
           }
        }
  
        if (defIncrPeriod == null)
        {
           throw new IllegalStateException(DEFAULT_INCREMENTAL_JOB_PERIOD + " not specified");
        }
  
        defaultIncrementalJobPeriod = Integer.valueOf(defIncrPeriod);
  
        if (fullBackupType == null)
        {
           throw new IllegalStateException(FULL_BACKUP_TYPE + " not specified");
        }
  
        if (incrementalBackupType == null)
        {
           throw new IllegalStateException(INCREMENTAL_BACKUP_TYPE + " not specified");
        }
     }
docs: Check read params and initialize.