When I clone a sheet and protect it: HSSFSheet sheet = workBook.cloneSheet(index); sheet.setProtect(true); I get this: java.lang.NullPointerException at org.apache.poi.hssf.usermodel.HSSFSheet.setProtect (HSSFSheet.java:847)
Fixed in 3.0-alpha2 with bug 37058 (svn r368554) *** This bug has been marked as a duplicate of bug 37058 ***