How to set plain header in docx file using apache poi?

Question

I would like to create a header for docx document using apache poi but I have difficulties. I have no working code to show. I would like to ask for some piece of code as sta

Answer 1

Based on the previous answer, just copy and paste:

public void test1() throws IOException{

    XWPFDocument sampleDoc = new XWPFDocument();
    XWPFHeaderFooterPolicy policy = sampleDoc.getHeaderFooterPolicy();
    //in an empty document always will be null
    if(policy==null){
        CTSectPr sectPr = sampleDoc.getDocument().getBody().addNewSectPr();
        policy = new  XWPFHeaderFooterPolicy( sampleDoc, sectPr );
    }

    if (policy.getDefaultHeader() == null && policy.getFirstPageHeader() == null
            && policy.getDefaultFooter() == null) {
        XWPFHeader headerD = policy.createHeader(policy.DEFAULT);
        headerD.getParagraphs().get(0).createRun().setText("Hello Header World!");


    } 
    FileOutputStream out = new FileOutputStream(System.currentTimeMillis()+"_test1_header.docx");
    sampleDoc.write(out);
    out.close();
    sampleDoc.close();
}