Mostly LGTM. This looks like a nice cleanup and should remove a lot of potential for lock contention. I like that a lot of the code gets a lot simpler too. SerializabilityUtil.java is some particularly embarrassing code that I helped write. This patch should allow that code to be refactored to be simpler in the future, I'd think.
http://gwt-code-reviews.appspot.com/716801/diff/14001/15001 File dev/core/src/com/google/gwt/dev/util/HttpHeaders.java (right): http://gwt-code-reviews.appspot.com/716801/diff/14001/15001#newcode65 dev/core/src/com/google/gwt/dev/util/HttpHeaders.java:65: * The Internet date format for HTTP. It would be great to add a comment here as to why we have to go through all this trouble in the first place. Just something like "The doc for DataFormat states: Date formats are not synchronized. It is recommended to create separate format instances for each thread. If multiple threads access a format concurrently, it must be synchronized externally." http://gwt-code-reviews.appspot.com/716801/diff/14001/15004 File user/src/com/google/gwt/user/server/rpc/AbstractRemoteServiceServlet.java (right): http://gwt-code-reviews.appspot.com/716801/diff/14001/15004#newcode33 user/src/com/google/gwt/user/server/rpc/AbstractRemoteServiceServlet.java:33: protected static final transient ThreadLocal<HttpServletRequest> perThreadRequest = Remove the "transient" keyword here and below. http://gwt-code-reviews.appspot.com/716801/diff/14001/15007 File user/src/com/google/gwt/user/server/rpc/impl/ConcurrentReferenceHashMap.java (right): http://gwt-code-reviews.appspot.com/716801/diff/14001/15007#newcode1025 user/src/com/google/gwt/user/server/rpc/impl/ConcurrentReferenceHashMap.java:1025: public ConcurrentReferenceHashMap(int initialCapacity, boolean userefid) { We need to be really clear about where this class came from, what version, what license it's under, etc. Are we sure we can just rebrand it as Apache? Is there any reason to move it from the jsr166y package to our own? Did we modify this? For example, I cannot find this particular constructor in the public versions (or any constructor overloads that take a boolean argument). http://gwt-code-reviews.appspot.com/716801/show -- http://groups.google.com/group/Google-Web-Toolkit-Contributors
