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
return taskID;
	}
	protected Object convertToType( Object value, String type )
	{
		try
		{
			if ( DesignChoiceConstants.PARAM_TYPE_BOOLEAN.equals( type ) )
			{
				return DataTypeUtil.toBoolean( value );
			}
			else if ( DesignChoiceConstants.PARAM_TYPE_DATETIME.equals( type ) )
			{
				return DataTypeUtil.toDate( value );
			}
			else if ( DesignChoiceConstants.PARAM_TYPE_DATE.equals( type ) )
			{
				return DataTypeUtil.toSqlDate( value );
			}
			else if ( DesignChoiceConstants.PARAM_TYPE_TIME.equals( type ) )
			{
				return DataTypeUtil.toSqlTime( value );
			}
			else if ( DesignChoiceConstants.PARAM_TYPE_DECIMAL.equals( type ) )
			{
				return DataTypeUtil.toBigDecimal( value );
			}
			else if ( DesignChoiceConstants.PARAM_TYPE_FLOAT.equals( type ) )
			{
				return DataTypeUtil.toDouble( value );
			}