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
Object paramValue, String type, ScalarParameterHandle paramHandle )
			throws ParameterValidationException
	{
		/*
		 * Validate based on parameter type
		 */
		if ( DesignChoiceConstants.PARAM_TYPE_DECIMAL.equals( type )
				|| DesignChoiceConstants.PARAM_TYPE_FLOAT.equals( type ) )
		{
			if ( paramValue instanceof Number )
				return true;
			throw new ParameterValidationException(
					MessageConstants.INVALID_PARAMETER_TYPE_EXCEPTION,
					new String[]{paramName, type, paramValue.getClass( ).getName( )} );
		}
		else if ( DesignChoiceConstants.PARAM_TYPE_DATETIME.equals( type ) )
		{
			if ( paramValue instanceof Date )
				return true;
			throw new ParameterValidationException(
					MessageConstants.INVALID_PARAMETER_TYPE_EXCEPTION,
					new String[]{paramName, type, paramValue.getClass( ).getName( )} );
		}
		else if ( DesignChoiceConstants.PARAM_TYPE_DATE.equals( type ) )
		{
			if ( paramValue instanceof java.sql.Date )
				return true;
			throw new ParameterValidationException(
					MessageConstants.INVALID_PARAMETER_TYPE_EXCEPTION,
					new String[]{paramName, type, paramValue.getClass( ).getName( )} );