Ethereum: How to communicate between Java and bitcoind?

Ethereum: A brief overview and communication between Java and Bitcoin

As a developer who works with Ethereum, you will probably find several libraries with which you can interact with blockchain, including interaction with the JSON RPC interface provided by Bitcoin. However, there are problems with communication between these languages ​​due to differences in syntax, data types and network protocols.

The problem: JSON RPC incompatibilities

JSON-RPC is a standard protocol that is used for communication between customers and servers and enables developers to interact with blockchain services such as Ethereum. However, the implementation of this protocol differs between Java and Bitcoin libraries. For example:

* JSON data type : JavaScript (used in Bitcoin) uses Number,Boolean etc. data types, while Java use,double, Stringetc.

* Methods RPC : JavaScript defines RPC methods using the Camelcase -Syntax ("Getbalance" vs. "Getbalance"), while Java requires suitable methods for suitable methods (e.g. "Getuseeranadress").

* Data setting : JavaScript usesJSON.STRINGY () ‘to serialize data, while the Java Java Library is used for de -review.

Find a compatible solution

Although it seems difficult to find an implementation that works in both languages, we will examine some possible solutions:

1. JSON-RPC libraries with specific language implementations

Some libraries such as [Jackson-Databind] ( (Java) implemented a way to work with Ethereum with their own specific language data types and serialization mechanisms.

2. Libraries and APIS third

There are libraries and APIs of third-party providers who offer an intermediate layer so that developers can interact with the JSON-RPC interface without being able to implement the underlying protocol manually. For example:

• [JSON-RPC API] ( An official node.js library for interaction with the Endpoint Json-RPC from Ethereum.

• [Api Ethereum Client Library] ( A Java library that simplifies communication with the Virtual Machine (EVM) from Ethereum.

3. Personalized implementation

In some cases, it may be possible to create a personalized implementation with Java and JavaScript languages. This approach requires considerable efforts and experience in the development of linguistic agnostic solutions.

Work example: Use Jackson-Databind

In order to demonstrate how to use Ethereum “Jackson-Databind” with the JSON RPC terminal, we assume that we have a simple Java customer who makes a request for the endpoint JSON-RPC:

“ Java

Import with.Fasterxml.jackson.databind.object mapper;

Import Java.io.ioException;

Main class of public class {

Public Static Void Main (String [] Args) starts ioexception {

// Create an instance of Object Mapper with the settings of the Jackson library

Object mapper Mapper = New Object Mapper ();

// Define the parameters of the JSON-RPC method (e.g. address, logHash)

Map params = new hashmap <> ();

String address = “0x1234567890abcdef”;

Blockid Blockhash = Blockid.Fromhex (“ABC123”);

// Create a requirement JSON-RPC

JSonnode Request = Mapper.Createobjectnode ()

.Put (“JSONRPC”, “2.0”)

.Put (“method”, “eth_getbalance”)

.Put (“params”, params)

.Tostring ();

// Send the request to the JSON RPC terminal

String Response = New Object Mapper (). Valuetojson (request);

// analyze the answer as an object JSON

Jsonnode Responsejson = mapper.Readtree (answer);

// extract the value of the JSON -Response equilibrium

String balance = responsejson.get (“result”). Astext ();

System.Out.