Thanks for your inquiry.
Yes, you can use Aspose.Words for Java to add content of a section to another section in the document, which in turn will enable you to delete section break(s) and add content of the section(s) under consideration to another one. You can get all the sections using getSections method of Document class, then use appendContent method of Section class to append content of any other section to it, and finally remove the section from sections array of the document. Here is the code snippet which appends all sections contents to the first section and removes all sections except the first one, might help you:
Document doc = new Document(csInputFilePath);
Section cSections = doc.getSections().toArray();
//Append content of all section to the first section
for (int i = 0; i < cSections.length; i++)
Section sect = cSections[i];
//Remove all sections but first
Additionally, you can also have a look here to explore sections and their usage in Aspose.Words for Java. Hope this helps. Please do let us know if you have any more queries.
Thanks a lot. It works great.