Please suggest me any Java API for RTF to DOCX Conversion. I have tried the following utilities but could not find anything useful for my requirement.

Aspose.Words for Java
The issue that we face with Aspose.Words for Java library is that some of the images present in RTF file are blown up in DOCX file.

OpenOffice
We tried to use OpenOffice for our conversion, but found that it does not support saving in DOCX format.

Please find the message in the forum

Yes it is, support was added in 3.0, although you can't save in that format.

[Solved] Batch conversion of .docx to PDF (View topic) • OpenOffice.org Community Forum

Apache POI
The Apache POI Java APIs is used for manipulating various file formats based upon the Office Open XML standards (OOXML) and Microsoft's OLE 2 Compound Document format (OLE2).

But it does not support reading RTF. Please find the information that we got from forums.

No, POI has no provisions for reading RTF. But the basic structure of RTF isn't complicated. If you spend some time with the specification (such as there is) and study a few simple RTF files, you should be able to write code that parses the file contents and extracts the actual text.

how to read rtf file and display in console? (Beginning Java forum at JavaRanch)

No. RTF is not an OLE 2 Compound Document Format (hence the header error), nor is it a closed format, nor even binary and there are plenty of libraries that can read/write it. POI only covers "nitch" formats (OLE 2 Compound Document based).

POI - User - Reading rtf files using POI-HWPF

JODConvertor

JODConverter is supporting DOCX as input but not as output format.

Please find the error trace when we tried converting RTF to DOCX.
Dec 27, 2010 8:16:51 AM com.artofsolving.jodconverter.openoffice.connectio n.AbstractOpenOfficeConnection connect
INFO: connected
Exception in thread "main" java.lang.IllegalArgumentException: unsupported conversion: from Rich Text Format to Microsoft Word 2007 XML

docx4j
docx4j is an open source Java library for manipulating OpenXML WordprocessingML documents, released under the Apache software licence.

It supports creating, reading and saving DOCX files and export them to PDF/HTML. But, it does not help in reading RTF file.

We have also come across utilities like Docmosis, Java2Word, javadocx and iText. But none of them helped in converting RTF to DOCX.

Any suggestion on this is much appreciated. Thanks