public static List<RegionInfo> createRegions(final Configuration conf, final Path rootDir,
    final TableDescriptor tableDescriptor, final RegionInfo[] newRegions, final RegionFillTask task)
    throws IOException {
    if (newRegions == null) return null;
    int regionNumber = newRegions.length;
    ThreadPoolExecutor exec = getRegionOpenAndInitThreadPool(conf,
      "RegionOpenAndInit-" + tableDescriptor.getTableName(), regionNumber);
    try {
      return createRegions(exec, conf, rootDir, tableDescriptor, newRegions, task);
    } finally {
      exec.shutdownNow();
    }
  }
Create new set of regions on the specified file-system. NOTE: that you should add the regions
to hbase:meta after this operation.
@param conf            {@link Configuration}
@param rootDir         Root directory for HBase instance
@param tableDescriptor description of the table
@param newRegions      {@link RegionInfo} that describes the regions to create
@param task            {@link RegionFillTask} custom code to populate region after creation
hbase-server/src/main/java/org/apache/hadoop/hbase/util/ModifyRegionUtils.java