[#5722] - Better error messages / error handling, sometimes we do not know where the error is

We should have a better error message, sometimes we do not know where the error is..

- Dont know the object that is being used
- Dont know the expression

It would be great to have a better error handling with that information.

 Compiling to file... C:\xxxxx\xxxxx.jasper
Compilation running time: 941!
 Filling report...
 Locale: português (Portugal)
 Time zone: Default
 Max number of records: 1.000
 Using report virtualizer... JRFileVirtualizer Size: 100 Swap directory: C:\Program Files\Jaspersoft\iReport-4.1.2;
Error filling print... java.lang.String cannot be cast to java.lang.Number
java.lang.ClassCastException: java.lang.String cannot be cast to java.lang.Number      at net.sf.jasperreports.engine.fill.JRIntegerSumIncrementer.increment(JRIntegerIncrementerFactory.java:299)      at net.sf.jasperreports.crosstabs.fill.calculation.MeasureDefinition$MeasureValue.addValue(MeasureDefinition.java:204)      at net.sf.jasperreports.crosstabs.fill.calculation.BucketingService.addData(BucketingService.java:324)      at net.sf.jasperreports.engine.fill.JRFillCrosstab$JRFillCrosstabDataset.customIncrement(JRFillCrosstab.java:797)      at net.sf.jasperreports.engine.fill.JRFillElementDataset.increment(JRFillElementDataset.java:177)      at net.sf.jasperreports.engine.fill.JRCalculator.calculateVariables(JRCalculator.java:164)      at net.sf.jasperreports.engine.fill.JRFillDatasetRun.detail(JRFillDatasetRun.java:226)      at net.sf.jasperreports.engine.fill.JRFillDatasetRun.iterate(JRFillDatasetRun.java:171)      at net.sf.jasperreports.engine.fill.JRFillDatasetRun.evaluate(JRFillDatasetRun.java:136)      at net.sf.jasperreports.engine.fill.JRFillElementDataset.evaluateDatasetRun(JRFillElementDataset.java:224)      at net.sf.jasperreports.engine.fill.JRFillCrosstab.evaluate(JRFillCrosstab.java:467)      at net.sf.jasperreports.engine.fill.JRFillElementContainer.evaluate(JRFillElementContainer.java:257)      at net.sf.jasperreports.engine.fill.JRFillBand.evaluate(JRFillBand.java:473)      at net.sf.jasperreports.engine.fill.JRVerticalFiller.fillColumnBand(JRVerticalFiller.java:2021)      at net.sf.jasperreports.engine.fill.JRVerticalFiller.fillDetail(JRVerticalFiller.java:755)      at net.sf.jasperreports.engine.fill.JRVerticalFiller.fillReportStart(JRVerticalFiller.java:265)      at net.sf.jasperreports.engine.fill.JRVerticalFiller.fillReport(JRVerticalFiller.java:128)      at net.sf.jasperreports.engine.fill.JRBaseFiller.fill(JRBaseFiller.java:836)      at net.sf.jasperreports.engine.fill.JRBaseFiller.fill(JRBaseFiller.java:746)      at net.sf.jasperreports.engine.fill.JRFiller.fillReport(JRFiller.java:58)      at net.sf.jasperreports.engine.JasperFillManager.fillReport(JasperFillManager.java:417)      at net.sf.jasperreports.engine.JasperFillManager.fillReport(JasperFillManager.java:247)      at com.jaspersoft.ireport.designer.compiler.IReportCompiler.run(IReportCompiler.java:879)      at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:572)      at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:997) 
Print not filled. Try to use an EmptyDataSource...