public static boolean isSubRegion(String fullPath) {
    boolean isSubRegion = false;
    if (null != fullPath) {
      int idx = fullPath.indexOf(SEPARATOR, SEPARATOR.length());
      if (idx >= 0) {
        isSubRegion = true;
      }
    }
    return isSubRegion;
  }
This method returns true if the last region in provided fullPath is a sub-region else it
returns false. If fullPath is "/REGION1" it would return false and if it is "/REGION1/REGION2",
it would return true, which means that Region2 is a sub-region.

@param fullPath full path of the region
@return true if given full path has sub-regions else return false
geode-core/src/main/java/org/apache/geode/internal/cache/PartitionedRegionHelper.java