public java.lang.Boolean getStrikethrough()//True if the text has a strikethrough.
CellData setUserEnteredValue = new CellData()
.setUserEnteredValue(new ExtendedValue().setStringValue("example text"));
CellFormat cellFormat = new CellFormat();
cellFormat.getTextFormat(new TextFormat().getStrikethrough());
setUserEnteredValue.setUserEnteredFormat(cellFormat);