Real World Java 9

Trisha Gee, developer advocate at JetBrains talks about new interesting features of Java 9
15 October 2017   531

The feature we always hear about whenever Java 9 is in the news is Jigsaw, modularity. But this doesn't scratch the same developer itch that Java 8's lambdas and streams did, and we're left with a vague sensation that the next version might not be that interesting.

Java 9 actually has a lot of great additions and changes to make development a bit nicer. These features can't be lumped under an umbrella term like Java 8's lambdas and streams, the changes are scattered throughout the APIs and language features that we regularly use.

In this presentation Trisha Gee shows, via live coding:

  • What the Java Platform Module System is and how to make your code modular
  • How we can use the new Flow API to utilise Reactive Programming
  • The improvements to the Streams API that make it easier to control infinite streams
  • How to the Collections convenience methods simplify code

Along the way we bump into other Java 9 features, including some of the additions to interfaces and changes to deprecation.

What is Web3j?

Small review of lightweight Java and Android library for integration with Ethereum clients
15 December 2017   839

What is webj3?

web3j is a lightweight, highly modular, reactive, type safe Java and Android library for working with Smart Contracts and integrating with clients (nodes) on the Ethereum network:

web3j architecture
Web3j Architecture

This allows you to work with the Ethereum blockchain, without the additional overhead of having to write your own integration code for the platform.

According to the developers, these are the features:

  • Complete implementation of Ethereum's JSON-RPC client API over HTTP and IPC
  • Ethereum wallet support
  • Auto-generation of Java smart contract wrappers to create, deploy, transact with and call smart contracts from native Java code (Solidity and Truffle definition formats supported)
  • Reactive-functional API for working with filters
  • Ethereum Name Service (ENS) support
  • Support for Parity's Personal, and Geth's Personal client APIs
  • Support for Infura, so you don't have to run an Ethereum client yourself
  • Comprehensive integration tests demonstrating a number of the above scenarios
  • Command line tools
  • Android compatible
  • Support for JP Morgan's Quorum via web3j-quorum

It has five runtime dependencies:

  • RxJava for its reactive-functional API
  • OKHttp for HTTP connections
  • Jackson Core for fast JSON serialisation/deserialisation
  • Bouncy Castle (Spongy Castle on Android) for crypto
  • Jnr-unixsocket for *nix IPC (not available on Android)

It also uses JavaPoet for generating smart contract wrappers.

Lear more at GitHub.