If you invoke WS using SEI through jaxws-rt, you might encounter an issue where your PERM space is filled with instances of com/sun/xml/ws/client/WSServiceDelegate$DelegatingLoader and you get a wonderful OutOfMemory PERMGEN error.
Looking at the code in http://grepcode.com/file/repo1.maven.org/maven2/com.sun.xml.ws/jaxws-rt/2.2.8/com/sun/xml/ws/client/WSServiceDelegate.java?av=f we see that each invokation to createEndpointIFBaseProxy will instantiate a new DelegatingLoader(loader1, loader2); (which is an inner class).... createEndpointIFBaseProxy is called for each getPort call... This inner class was not there in previous versions of the library.
So you might want to try an older version of the library ... or to apply some caching trick so as to avoid a getPort call for every WS invokation (if the WS is always the same, it seems to me that you don't need to go through all the work of creating a new Proxy for each call.... )
Looking at the code in http://grepcode.com/file/repo1.maven.org/maven2/com.sun.xml.ws/jaxws-rt/2.2.8/com/sun/xml/ws/client/WSServiceDelegate.java?av=f we see that each invokation to createEndpointIFBaseProxy will instantiate a new DelegatingLoader(loader1, loader2); (which is an inner class).... createEndpointIFBaseProxy is called for each getPort call... This inner class was not there in previous versions of the library.
So you might want to try an older version of the library ... or to apply some caching trick so as to avoid a getPort call for every WS invokation (if the WS is always the same, it seems to me that you don't need to go through all the work of creating a new Proxy for each call.... )