Date format not being accepted by Decision Server

Issue

When sending the attribute of type Date to the Decision Server, for example:

<flightDate>2015-10-11 22:33:44.5 z</flightDate>

Following error is observed:

Error calling container custom: com.thoughtworks.xstream.converters.ConversionException: Cannot parse date 2015-10-11 22:33:44.5 z
---- Debugging information ----
class               : java.util.Date
required-type       : java.util.Date
converter-type      : com.thoughtworks.xstream.converters.SingleValueConverterWrapper
wrapped-converter   : com.thoughtworks.xstream.converters.basic.DateConverter
Default date pattern: yyyy-MM-dd HH:mm:ss.S z
Default era date pattern: yyyy-MM-dd G HH:mm:ss.S z
Alternative date pattern: yyyy-MM-dd HH:mm:ss.S z
Alternative date pattern[1]: yyyy-MM-dd HH:mm:ss.S a
Alternative date pattern[2]: yyyy-MM-dd HH:mm:ssz
Alternative date pattern[3]: yyyy-MM-dd HH:mm:ss z
Alternative date pattern[4]: yyyy-MM-dd HH:mm:ssa
path                : /batch-execution/insert/com.sample.Flight/flightDate
line number         : 26
class[1]            : com.sample.Flight.
converter-type[1]   : com.thoughtworks.xstream.converters.reflection.ReflectionConverter
class[2]            : org.drools.core.command.runtime.rule.InsertObjectCommand
converter-type[2]   : org.drools.core.runtime.help.impl.XStreamXML$InsertConverter
class[3]            : org.drools.core.command.runtime.BatchExecutionCommandImpl
version             : 1.4.7
-------------------------------

How to correctly send or receive date including Date values to the Decision Server?