// For complete examples and data files, please go to https://github.com/aspose-words/Aspose.Words-for-Java
// The path to the documents directory.
String dataDir = Utils.getDataDir(SetCurrentStateOfCheckBox.class);

// Open the document.
Document doc = new Document(dataDir + "CheckBoxTypeContentControl.docx");
DocumentBuilder builder = new DocumentBuilder(doc);
StructuredDocumentTag SdtCheckBox  = (StructuredDocumentTag)doc.getChild(NodeType.STRUCTURED_DOCUMENT_TAG, 0, true);

//StructuredDocumentTag.Checked property gets/sets current state of the Checkbox SDT
if (SdtCheckBox.getSdtType() == SdtType.CHECKBOX)
    SdtCheckBox.setChecked(true);

doc.save(dataDir + "output.doc");