Modular Development with JDK 9

Alex Buckley, Editor of JLS/JVMS at Oracle covers the topic of Modular Development with JDK 9
03 October 2017   571

What does strong encapsulation mean in JDK 9?  How do you migrate your current application to modules? Alex Buckley explains in great detail the key concepts behind modules.  He describes how the module system can improve the structure of your code, how you can migrate your application progressively by mixing modular and non-modular code, and how a modular JDK enables better compatibility.  

The module system is a big part of the JDK 9 release, which is planned for September. With JDK 9, you will still be able to run your applications on the classpath. The new module system is built into the Java language and the virtual machine. Your applications and the libraries you use can be packaged, tested and deployed as modules managed by the module system. A module is essentially a set of packages that make sense being grouped together and is designed for reuse.  Since the full platform is modular, the modular system is more reliable, easier to maintain and secure. Those benefits are shown in examples described through out this presentation.  

What is Web3j?

Small review of lightweight Java and Android library for integration with Ethereum clients
15 December 2017   833

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.