Well, I tested conditional formattings feature using Aspose.Cells for java APIs and it works fine.
Following is my sample code:
//Instantiating an Workbook object
Workbook workbook = new Workbook();
Worksheet sheet = workbook.getSheet(0);
ConditionalFormattings cfs = sheet.getConditionalFormattings();
//The first method:adds an empty conditional formatting
int index = cfs.add();
FormatConditions fcs = cfs.get(index);
//Sets the conditional format range.
//Sets condition formulas.
int conditionIndex = fcs.addFormatCondition(FormatConditionType.CELL_VALUE,OperatorType.BETWEEN,"=A2","100");
FormatCondition fc = fcs.getFormatCondition(conditionIndex);
int conditionIndex2 = fcs.addFormatCondition(FormatConditionType.CELL_VALUE,OperatorType.BETWEEN,"50","100");
// The second method
int formatCondtionsIndex = cfs.add(new CellArea(9,1,10,1),FormatConditionType.CELL_VALUE, OperatorType.BETWEEN,"=A1","100");
Which version of Aspose.Cells for java you are using. Please try the attached version.
If you still find the problem, post you sample code here.