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231 lines
11 KiB
Markdown
231 lines
11 KiB
Markdown
---
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html: get-started-using-java.html
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parent: get-started.html
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funnel: Build
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doc_type: Tutorials
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category: Get Started
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blurb: Build a simple Java app that interacts with the XRP Ledger.
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cta_text: Build an XRP Ledger-connected app
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top_nav_name: Java
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top_nav_grouping: Get Started
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filters:
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- include_code
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labels:
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- Development
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showcase_icon: assets/img/logos/java.svg
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---
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# Get Started Using Java
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This tutorial walks you through the basics of building a very simple XRP Ledger-connected application using [`xrpl4j`](https://github.com/XRPLF/xrpl4j), a pure Java library that makes it easy to interact with the XRP Ledger.
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This tutorial is intended for beginners and should take no longer than 30 minutes to complete.
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## Learning Goals
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In this tutorial, you'll learn:
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* The basic building blocks of XRP Ledger-based applications.
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* How to connect to the XRP Ledger using `xrpl4j`.
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* How to generate a wallet on the [Testnet](xrp-testnet-faucet.html) using `xrpl4j`.
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* How to use the `xrpl4j` library to look up information about an account on the XRP Ledger.
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* How to put these steps together to create a simple Java app.
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## Requirements
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* The `xrpl4j` library supports Java 1.8 and later.
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* A project management tool such as [Maven](https://maven.apache.org/) or [Gradle](https://gradle.org/). <!-- SPELLING_IGNORE: gradle -->
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## Installation
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The [`xrpl4j` library](https://github.com/XRPLF/xrpl4j) is available on [Maven Central](https://search.maven.org/artifact/org.xrpl/xrpl4j-parent).
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`xrpl4j` is split into multiple artifacts, which can be imported as needed.
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In this tutorial, you will need the [xrpl4j-client](https://javadoc.io/doc/org.xrpl/xrpl4j-client/latest/index.html), [xrpl4j-address-codec](https://javadoc.io/doc/org.xrpl/xrpl4j-address-codec/latest/index.html), [xrpl4j-keypairs](https://javadoc.io/doc/org.xrpl/xrpl4j-keypairs/latest/index.html), and [xrpl4j-model](https://javadoc.io/doc/org.xrpl/xrpl4j-model/latest/index.html) modules. <!-- SPELLING_IGNORE: keypairs -->
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To install with Maven, add the following to your project's `pom.xml` file and then run `mvn install`:
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```xml
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<dependencies>
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<dependency>
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<groupId>org.xrpl</groupId>
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<artifactId>xrpl4j-client</artifactId>
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<version>2.0.0</version>
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</dependency>
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<dependency>
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<groupId>org.xrpl</groupId>
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<artifactId>xrpl4j-address-codec</artifactId>
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<version>2.0.0</version>
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</dependency>
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<dependency>
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<groupId>org.xrpl</groupId>
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<artifactId>xrpl4j-keypairs</artifactId>
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<version>2.0.0</version>
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</dependency>
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<dependency>
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<groupId>org.xrpl</groupId>
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<artifactId>xrpl4j-model</artifactId>
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<version>2.0.0</version>
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</dependency>
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</dependencies>
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```
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Check out the [xrpl4j sample project](https://github.com/XRPLF/xrpl4j-sample) for a full Maven project containing the code from this tutorial.
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## Start Building
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{% set n = cycler(* range(1,99)) %}
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When you're working with the XRP Ledger, there are a few things you'll need to manage, whether you're adding XRP into your [wallet](wallets.html), integrating with the [decentralized exchange](decentralized-exchange.html), or [issuing tokens](issued-currencies.html). This tutorial walks you through basic patterns common to getting started with all of these use cases and provides sample code for implementing them.
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Here are the basic steps you'll need to cover for almost any XRP Ledger project:
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1. [Connect to the XRP Ledger.](#1-connect-to-the-xrp-ledger)
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1. [Generate a wallet.](#2-generate-wallet)
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1. [Query the XRP Ledger.](#3-query-the-xrp-ledger)
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### {{n.next()}}. Connect to the XRP Ledger
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To make queries and submit transactions, you need to establish a connection to the XRP Ledger. To do this with `xrpl4j`,
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you can use an [`XrplClient`](https://javadoc.io/doc/org.xrpl/xrpl4j-client/latest/org/xrpl/xrpl4j/client/XrplClient.html):
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{{ include_code("_code-samples/get-started/java/GetAccountInfo.java", start_with="// Construct a network client", end_before="// Create a Wallet using a WalletFactory", language="java") }}
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#### Connect to the production XRP Ledger
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The sample code in the previous section shows you how to connect to the Testnet, which is one of the available [parallel networks](parallel-networks.html). When you're ready to integrate with the production XRP Ledger, you'll need to connect to the Mainnet. You can do that in two ways:
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* By [installing the core server](install-rippled.html) (`rippled`) and running a node yourself. The core server connects to the Mainnet by default, but you can [change the configuration to use Testnet or Devnet](connect-your-rippled-to-the-xrp-test-net.html). [There are good reasons to run your own core server](the-rippled-server.html#reasons-to-run-your-own-server). If you run your own server, you can connect to it like so:
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final HttpUrl rippledUrl = HttpUrl.get("http://localhost:5005/");
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XrplClient xrplClient = new XrplClient(rippledUrl);
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See the example [core server config file](https://github.com/ripple/rippled/blob/c0a0b79d2d483b318ce1d82e526bd53df83a4a2c/cfg/rippled-example.cfg#L1562) for more information about default values.
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* By using one of the available [public servers][]:
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final HttpUrl rippledUrl = HttpUrl.get("https://s2.ripple.com:51234/");
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XrplClient xrplClient = new XrplClient(rippledUrl);
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### {{n.next()}}. Generate wallet
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To store value and execute transactions on the XRP Ledger, you need to create a wallet:
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a [set of keys](cryptographic-keys.html#key-components) and an [address](accounts.html#addresses) that's
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been [funded with enough XRP](accounts.html#creating-accounts) to meet the [account reserve](reserves.html).
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The address is the identifier of your account and you use the [private key](cryptographic-keys.html#private-key) to
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sign transactions that you submit to the XRP Ledger. For production purposes, you should take care to store your keys and set up
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a [secure signing method](set-up-secure-signing.html).
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For testing and development purposes, you can use the [XRP Faucets](xrp-testnet-faucet.html) to fund
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an account on the Testnet or Devnet.
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To make it easy to generate a new, random Wallet, `xrpl4j` provides the [`DefaultWalletFactory`](https://javadoc.io/doc/org.xrpl/xrpl4j-keypairs/latest/org/xrpl/xrpl4j/wallet/DefaultWalletFactory.html).
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{{ include_code("_code-samples/get-started/java/GetAccountInfo.java", start_with="// Create a Wallet using a WalletFactory", end_before="// Get the Classic and X-Addresses from testWallet", language="java") }}
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The result of a call to `walletFactory.randomWallet(true).wallet()` is a [`Wallet` instance](https://javadoc.io/doc/org.xrpl/xrpl4j-keypairs/latest/org/xrpl/xrpl4j/wallet/Wallet.html):
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```
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System.out.println(testWallet);
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// print output
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Wallet {
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privateKey= -HIDDEN-,
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publicKey=ED90635A6F2A5905D3D5CD2C14905FFB2D838185993576CA4CEE24A920D0D6BD6B,
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classicAddress=raj5eirfEpbN9YzG9FzB8ZPNyjpFvH6ycV,
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xAddress=T76mQFr9zLGi2LCjVDgJ7mEQCk4767SdEL32mZFygpdGcFf,
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isTest=true
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}
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```
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In order to fund the account on the XRP Ledger, you can use a `FaucetClient` connected to the XRP Ledger Testnet:
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{{ include_code("_code-samples/get-started/java/GetAccountInfo.java", start_with="// Fund the account using the testnet Faucet", end_before="// Look up your Account Info", language="java") }}
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### {{n.next()}}. Query the XRP Ledger
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You can query the XRP Ledger to get information about [a specific account](account-methods.html), [a specific transaction](tx.html), the state of a [current or a historical ledger](ledger-methods.html), and [the XRP Ledger's decentralized exchange](path-and-order-book-methods.html). You need to make these queries, among other reasons, to look up account info to follow best practices for [reliable transaction submission](reliable-transaction-submission.html).
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Here, we'll use the [`XrplClient` we constructed](#1-connect-to-the-xrp-ledger) to look up information about the [wallet we generated](#2-generate-wallet) in the previous step.
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{{ include_code("_code-samples/get-started/java/GetAccountInfo.java", start_with="// Look up your Account Info", end_before="// Print the result", language="java") }}
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### {{n.next()}}. Putting it all together
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Using these building blocks, we can create a simple Java app that:
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1. Generates a wallet on the Testnet.
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2. Connects to the XRP Ledger.
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3. Looks up and prints information about the account you created.
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```java
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{% include '_code-samples/get-started/java/GetAccountInfo.java' %}
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```
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To run the app, you can download the code from [Github](https://github.com/XRPLF/xrpl4j-sample) and run `GetAccountInfo` either
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from your IDE or from the command line.
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```sh
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git clone https://github.com/XRPLF/xrpl4j-sample.git
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cd xrpl4j-sample
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mvn compile exec:java -Dexec.mainClass="org.xrpl.xrpl4j.samples.GetAccountInfo"
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```
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You should see output similar to this example:
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```sh
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Running the GetAccountInfo sample...
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Constructing an XrplClient connected to https://s.altnet.rippletest.net:51234/
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Generated a wallet with the following public key: ED015D922B5EACF09DF01168141FF27FA6229B0FAB9B4CD88D2B6DA036090EFAA4
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Classic Address: rBXHGshqXu3Smy9FUsQTmo49bGpQUQEm3X
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X-Address: T7yMiiJJCmgY2yg5WB2davUedDeBFAG5B8r9KHjKCxDdvv3
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Funded the account using the Testnet faucet.
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AccountInfoResult{
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status=success,
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accountData=AccountRootObject{
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ledgerEntryType=ACCOUNT_ROOT,
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account=rBXHGshqXu3Smy9FUsQTmo49bGpQUQEm3X,
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balance=1000000000,
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flags=0,
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ownerCount=0,
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previousTransactionId=0000000000000000000000000000000000000000000000000000000000000000,
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previousTransactionLedgerSequence=0,
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sequence=17178149,
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signerLists=[],
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index=0DC1B13C73A7F3D2D82446526D0C5D08E88F89BA442D54291117F1A08E447685
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},
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ledgerCurrentIndex=17178149,
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validated=false
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}
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```
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#### Interpreting the response
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The response fields contained in `AccountInfoResult` that you want to inspect in most cases are:
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* `accountData.sequence` — This is the sequence number of the next valid transaction for the account. You need to specify the sequence number when you prepare transactions.
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* `accountData.balance` — This is the account's balance of XRP, in drops. You can use this to confirm that you have enough XRP to send (if you're making a payment) and to meet the [current transaction cost](transaction-cost.html#current-transaction-cost) for a given transaction.
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* `validated` — Indicates whether the returned data is from a [validated ledger](ledgers.html#open-closed-and-validated-ledgers). When inspecting transactions, it's important to confirm that [the results are final](finality-of-results.html) before further processing the transaction. If `validated` is `true` then you know for sure the results won't change. For more information about best practices for transaction processing, see [Reliable Transaction Submission](reliable-transaction-submission.html).
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For a detailed description of every response field, see [account_info](account_info.html#response-format).
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## Keep on building
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Now that you know how to use `xrpl4j` to connect to the XRP Ledger, generate a wallet, and look up information about an account, you can also use `xrpl4j` to:
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* [Send XRP](send-xrp.html).
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* [Set up secure signing](set-up-secure-signing.html) for your account.
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<!--{# common link defs #}-->
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{% include '_snippets/rippled-api-links.md' %}
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{% include '_snippets/tx-type-links.md' %}
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{% include '_snippets/rippled_versions.md' %}
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