code: @Deprecated
      public String getSkeletonAllowingDuplicates(String pattern) {
          synchronized (this) { // synchronized since a getter must be thread-safe
              current.set(pattern, fp, true);
              return current.toString();
          }
      }
docs: Same as getSkeleton, but allows duplicates
  
  @param pattern Input pattern, such as "dd/MMM"
  @return skeleton, such as "MMMdd"
  @deprecated This API is ICU internal only.
  @hide original deprecated declaration
  @hide draft / provisional / internal are hidden on Android