I needed a way to re-use an Excel worksheet. The existing B4J library has no methods for this, and I couldn't find anything related on this forum. So I used the Java object to implement what I needed. The solution is based on StackOverflow suggestions.
Sub clearSheet(wb As PoiWorkbook, sheetNum As Int) Dim theSheet As PoiSheet = wb.GetSheet(sheetNum) Dim jo As JavaObject = theSheet For j = theSheet.LastRowNumber To 0 Step -1 Dim aRow As PoiRow = theSheet.GetRow(j) If aRow.isinitialized Then jo.RunMethod("removeRow", Array(aRow)) Next Dim nregions As Int = jo.RunMethod("getNumMergedRegions", Array()) For j = nregions-1 To 0 Step -1 jo.RunMethod("removeMergedRegion", Array(j)) Next Log("Number of rows = " & theSheet.LastRowNumber) Log("Number of merged regions = " & jo.RunMethod("getNumMergedRegions", Array())) End Sub