maven 编译异常：com.thoughtworks.xstream.converters.ConversionException

今天用maven编译，报以奇怪异常：

mvn package -Dmaven.test.skip=true

[INFO] ------------------------------------------------------------------------

[INFO] Trace

com.thoughtworks.xstream.converters.ConversionException: Cannot construct org.ap

ache.maven.plugin.war.util.WebappStructure as it does not have a no-args constru

ctor

---- Debugging information ----

message             : Cannot construct org.apache.maven.plugin.war.util.WebappSt

ructure as it does not have a no-args constructor

cause-exception     : com.thoughtworks.xstream.converters.reflection.ObjectAcces

sException

cause-message       : Cannot construct org.apache.maven.plugin.war.util.WebappSt

ructure as it does not have a no-args constructor

class               : org.apache.maven.plugin.war.util.WebappStructure

required-type       : org.apache.maven.plugin.war.util.WebappStructure

path                : /webapp-structure

line number         : 1

-------------------------------

经查与JDK版本有关，1.7版本会报以上错误。换成1.6，果断成功。