Bug 202254 Exception is thrown when category values are null and type of X axis is set to DateTime
chart/org.eclipse.birt.chart.engine/src/org/eclipse/birt/chart/model/data/impl/DataPackageImpl.java
this.getOrthogonalSampleData( ),
				null,
				"orthogonalSampleData", null, 1, -1, SampleData.class, !IS_TRANSIENT, !IS_VOLATILE, IS_CHANGEABLE, IS_COMPOSITE, !IS_RESOLVE_PROXIES, !IS_UNSETTABLE, IS_UNIQUE, !IS_DERIVED, IS_ORDERED ); 
		initEReference( getSampleData_AncillarySampleData( ),
				this.getBaseSampleData( ),
				null,
				"ancillarySampleData", null, 1, -1, SampleData.class, !IS_TRANSIENT, !IS_VOLATILE, IS_CHANGEABLE, IS_COMPOSITE, !IS_RESOLVE_PROXIES, !IS_UNSETTABLE, IS_UNIQUE, !IS_DERIVED, IS_ORDERED ); 
		initEClass( seriesDefinitionEClass,
				SeriesDefinition.class,
				"SeriesDefinition", !IS_ABSTRACT, !IS_INTERFACE, IS_GENERATED_INSTANCE_CLASS ); 
		initEReference( getSeriesDefinition_Query( ),
				this.getQuery( ),
				null,
				"query", null, 1, 1, SeriesDefinition.class, !IS_TRANSIENT, !IS_VOLATILE, IS_CHANGEABLE, IS_COMPOSITE, !IS_RESOLVE_PROXIES, !IS_UNSETTABLE, IS_UNIQUE, !IS_DERIVED, IS_ORDERED ); 
		initEReference( getSeriesDefinition_SeriesPalette( ),
				theAttributePackage.getPalette( ),
				null,
				"seriesPalette", null, 1, 1, SeriesDefinition.class, !IS_TRANSIENT, !IS_VOLATILE, IS_CHANGEABLE, IS_COMPOSITE, !IS_RESOLVE_PROXIES, !IS_UNSETTABLE, IS_UNIQUE, !IS_DERIVED, IS_ORDERED ); 
		initEReference( getSeriesDefinition_SeriesDefinitions( ),
				this.getSeriesDefinition( ),
				null,
				"seriesDefinitions", null, 1, -1, SeriesDefinition.class, !IS_TRANSIENT, !IS_VOLATILE, IS_CHANGEABLE, IS_COMPOSITE, !IS_RESOLVE_PROXIES, !IS_UNSETTABLE, IS_UNIQUE, !IS_DERIVED, IS_ORDERED ); 
		initEReference( getSeriesDefinition_FormatSpecifier( ),
				theAttributePackage.getFormatSpecifier( ),
				null,
				"formatSpecifier", null, 1, 1, SeriesDefinition.class, !IS_TRANSIENT, !IS_VOLATILE, IS_CHANGEABLE, IS_COMPOSITE, !IS_RESOLVE_PROXIES, !IS_UNSETTABLE, IS_UNIQUE, !IS_DERIVED, IS_ORDERED ); 
		initEReference( getSeriesDefinition_Series( ),
				theComponentPackage.getSeries( ),
				null,
				"series", null, 1, -1, SeriesDefinition.class, !IS_TRANSIENT, !IS_VOLATILE, IS_CHANGEABLE, IS_COMPOSITE, !IS_RESOLVE_PROXIES, !IS_UNSETTABLE, IS_UNIQUE, !IS_DERIVED, IS_ORDERED );