Quite a lot of code in the libraries and a bit in Hotspot use 'int' or 'jint' as a synonym for socklen_t. socklen_t is an unsigned value on Unixen, and Hotspot typedef's it to int on Windows in JDK8 and #include's winsock2.h in tip. It would be nice to clean up the whole thing. I've attached Hotspot and library diffs for JDK8 and marked this as core-libs, even though there's a bit of Hotspot in JDK8.