Writing scalable server applications in the Java™ programming language has always been difficult. Before the advent of the Java New I/O API (NIO), thread management issues made it impossible for a server to scale to thousands of users. The Grizzly NIO framework has been designed to help developers to take advantage of the Java™ NIO API.
... this behavior isn't required anymore and is causing issues with browsers.
See EncoderUtils and DecoderUtils in the http2 module.