Bug 202236 When select NULL value for multi-value parameter, cause NPE.
Description: When select NULL value for multi-value parameter, cause NPE. Build number: 2.2.1 Steps to reproduce: 1, New a list parameter, check Allow multi-value, uncheck isRequired 2, Select parameter data type as Date 3, Add some items into list 4, Preview 5, Select Null Value item in list Expected result: Can accept Null value for multi-value parameter Actual result: Cause NPE.
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/api/impl/EngineTask.java
}
		else
		{
			Object renderContext = appContext
					.get( EngineConstants.APPCONTEXT_HTML_RENDER_CONTEXT );
			if ( renderContext instanceof HTMLRenderContext )
			{
				HTMLRenderContext htmlContext = (HTMLRenderContext) renderContext;
				mergeOption( renderOptions, HTMLRenderOption.BASE_IMAGE_URL,
						htmlContext.getBaseImageURL( ) );
				mergeOption( renderOptions, HTMLRenderOption.BASE_URL,
						htmlContext.getBaseURL( ) );
				mergeOption( renderOptions, HTMLRenderOption.IMAGE_DIRECTROY,
						htmlContext.getImageDirectory( ) );
				mergeOption( renderOptions,
						HTMLRenderOption.SUPPORTED_IMAGE_FORMATS, htmlContext
								.getSupportedImageFormats( ) );
			}
		}
		
		
		HashMap options = new HashMap( );
		
		HashMap configs = engine.getConfig( ).getEmitterConfigs( );
		
		
		IRenderOption defaultOptions = (IRenderOption) configs
				.get( IEngineConfig.DEFAULT_RENDER_OPTION );
		if ( defaultOptions == null )
		{