Ethereum java client

1. Ethereum also uses blockchain technology, but it is more convenient to use than bitcoin's blockchain Turing, which is complete and open source. Anyone can create their own application on the basis of Ethereum

2.

Blockchain projects require high efficiency, so most of the core source code development is using C / C + +. However, if you are doing a blockchain project, unless you need to make a lot of adjustments to the source code, you may not choose to use Java. For general DAPP applications, java development should also be a good choice. For example, in the case of Ethereum blockchain, there is a web3j class library for Java, which is very convenient; Bitcoin has bitcoin J class library, which is also easy to use. It still depends on the level of application, what to do, and the situation of the team

share two Java blockchain tutorials:

1. java bitcoin details

2. java Ethereum development

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3. My computer - & gt; Attribute - & gt; Advanced - & gt; Environment variables - & gt; Add the following environment variables to the system variables:
java_ The home value is: the directory where JDK is installed, and mine is C: &# 92; Program Files\ Java\ jdk1.6.0_ 34
the classpath value is:;% JAVA_ HOME%\ lib\ tools.jar;% JAVA_ HOME%\ lib\ dt.jar;% JAVA_ HOME%\ bin;( Pay attention to the & quot& quot; To add)
Path: append at the beginning.;% JAVA_ HOME%\ bin;% JAVA_ HOME%\ jre\ bin;( Pay attention to the & quot& quot; To add)

after the installation, you can check whether the JDK is installed successfully. Open the CMD window and enter Java – version to view the version information of JDK.

4. Generally speaking, undefined index is the exact writing problem in the process of writing. Notice generally prompts for errors that are not directly related to the execution of code, but don't forget that notice sometimes returns some rendant error information

5. There is no inevitable relationship between whether the virtual currency will disappear or not and whether it can not be used on the third-party platform. Online third-party trading platform can only say that this kind of currency has another platform for trading, which shows that this kind of currency is more reliable
Ruitai coin has not been launched on the third-party platform, but it is rumored that it will also be launched on the third-party platform.

6.

Generally speaking, the steps of deploying smart contract are as follows:

1. start an Ethereum node (such as geth or testrpc)

2. use Solc to compile smart contracts=& gt; Get the binary code

3. deploy the compiled contract to the network This step will consume Ethernet currency, and you need to use the default address or specified address of your node to sign the contract.)=& gt; Get the blockchain address and ABI of the contract (JSON representation of the contract interface, including variables, events and callable methods) The author confused ABI with contract interface here. ABI is the binary representation of the contract interface.)

4. use the JavaScript API provided by web3.js to call the contract Depending on the type of call, it may consume Ethernet currency.)

7. QT Java I play stock currency QT language can be mined, graphics card computing power

8. Truffle is a world-class development environment, testing framework, Ethereum resource management channel, dedicated to making Ethereum development easier, truffle has the following:
built in smart contract compilation, linking, deployment and binary file management
automatic contract testing under rapid development
scripted and extensible deployment and publishing framework
the network environment management function deployed to no matter how many public or private networks
uses the package management provided by ethpm & NPM and erc190 standard
a direct interactive console that communicates directly with the contract (after writing the contract, you can verify it on the command line)
the configurable construction process supports tight integration
external scripts can be executed in truffle environment< Truffle is the most popular development framework, whose mission is to make development easier
installation method:
$NPM install - G truffle
environment requirements
nodejs 5.0 +
windows, Linux, or Mac OS X
truffle needs Ethereum client and supports standard JSON RPC API. For development, some are more suitable, which will be introced in the following chapters (for example, testrpc provides real-time feedback ring coding and debugging)
suggestions for Windows users
if you are a Windows user, we recommend that you use PowerShell or git bash to install and use the truffle framework. These two shell environments provide more convenient features than the default
if you have to use the command line, see the discussion here on how to configure truffle.

9. What is the relationship between JCP mall and Ethereum
this bosom friend. JCP mall is a mall that contains JCP operation mode. To understand JCP mall, we must first understand JCP

JCP maintenance specifications include J2ME, J2SE, J2EE, XML, OSS, Jain, etc. Organization members can submit JSR (Java specification requests) and enter the next version of the specification after passing a specific program
Ethereum is an open source public blockchain platform with smart contract function, which provides decentralized Ethereum virtual machine to process point-to-point contract through its special cryptocurrency ether (ETH)
the concept of Ethereum was first proposed by vitalik buterin, a programmer, from 2013 to 2014, inspired by bitcoin, to the effect of "next generation cryptocurrency and decentralized application platform". It began to develop through ICO crowdfunding in 2014
as of February 2018, Ethernet is the second highest cryptocurrency in terms of market value, second only to bitcoin.