• Project structure changes
• General API changes
• Buffer API changes
• ChannelBuffer → ByteBuf
• ByteBuf is not an interface but an abstract class
• Most buffers are dynamic with maximum capacity
• New buffer type: CompositeByteBuf
• Predictable NIO buffer conversion
• Little endian support changes
• Pooled buffers
• ByteBuf is always reference counted
• Automatic buffer leak detection
• io.netty.util.concurrent
• Channel API changes
• Revamped ChannelHandler interface
• Upstream → Inbound, Downstream → Outbound
• New ChannelHandler type hierarchy
• ChannelHandler with no event object
• Simplified channel state model
• write() does not flush automatically
• Sensible and less error-prone inbound traffic suspension
• Suspension of accepting incoming connections
• Half-closed sockets
• Flexible I/O thread allocation
• Ability to create a Channel from an existing JDK socket
• Deregistration and re-registration of a Channel from·to an I/O thread
• Scheduling an arbitrary task to be run by an I/O thread
• Simplified shutdown
• Type-safe ChannelOption
• AttributeMap
• New bootstrap API
• ChannelPipelineFactory → ChannelInitializer
• ChannelFuture → ChannelFuture and ChannelPromise
• Well-defined thread model
• Write Ordering - Mix EventLoop thread and other threads
• No more ExecutionHandler - it's in the core.
• Codec framework changes
• Codec embedder → EmbeddedChannel
• HTTP codec
• Changes in transport implementations
• Case study: porting the Factorial example
• Porting the server
• Porting the client