Java connection to Ethereum

1.

Ethereum is an implementation of blockchain. In Ethereum network, many nodes are connected with each other to form Ethereum network:

Ethereum node software provides two core functions: data storage and contract code execution

in each Ethereum node, complete blockchain data is stored. Ethereum not only saves the transaction data on the chain, but also saves the compiled contract code on the chain

At the same time, a virtual machine is provided to execute the contract code

Ethereum virtual machine

Ethereum blockchain not only stores data and code, but also contains a virtual machine (EVM) in each node to execute contract code - it sounds like a computer operating system

in fact, this is the core difference between Ethereum and bitcoin: the existence of virtual machine has brought blockchain into the era of 2.0 and made blockchain a friendly platform for application developers for the first time

the above content comes from the introction course of Ethereum DAPP development

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. Okex. I've been using it. Shi Yuzhu has shares

7. There is no problem at all, but relatively speaking, we must buy some reliable ones, because we must pay attention to them.

8. 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.