I try to transfer file with Mtom and it is working pretty good until i use SoapHandler to verify client signature. SoapHandler keeps all message and changes it to base64 encoded. So when i try to get huge file, Jvm throws heap size exception. Do you guys know any ways to solve this problem?
The Java JRE comes with a JAX-WS Provider. This provider has what I would consider a bug. If a SoapHandler is added, either by directly getting the HandlerChain or by using a HandlerResolver, the message, which was correctly created using MTOM, is deconstructed and the attachment(s) are placed inline within the SOAP message. If the attachments are large, this can lead to very poor performance or out of memory errors.
The only solution I have found is to use another JAX-WS provider. From testing, Axis2 seems to work perfectly (although it has a huge number of dependencies). Simply placing another provider on the classpath will cause it to be used. Java looks for a file in META-INF/services named javax.xml.ws.spi.Provider. If this file is found, it will use the Provider specified. The main Axis2 jar will include this file to ensure the Axis2 provider is used. Other Providers may also solve this problem.
Because of this automatic Provider detection, you may find your application does or does not have this problem depending on where it is running. For example, if you deploy an application to IBM WebSphere it already has overridden the default Provider and you will not have this issue. Likely other Application Servers also have overridden the default Provider. If you can get ahold of a copy, IBM also provides a very nice jar, com.ibm.jaxws.thinclient_7.0.0.jar, that has Axis2 packaged in it. This can only be used for standalone applications (those not running in WebSphere), but it is very convenient and resolves this issue.
来源：https://stackoverflow.com/questions/12002632/mtom-not-working-when-using-soaphandler