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### Welcome to bitcoinj

The bitcoinj library is a Java implementation of the Bitcoin protocol, which allows it to maintain a wallet and send/receive transactions without needing a local copy of Bitcoin Core. It comes with full documentation and some example apps showing how to use it.

### Technologies

* Java 8+ (needs Java 8 API or Android 7.0 API, compiles to Java 8 bytecode) and Gradle 4.4+ for the `core` module
* Java 11+ and Gradle 4.4+ for `tools`, `wallettool` and `examples`
* Java 11+ and Gradle 4.10+ for the JavaFX-based `wallettemplate`
* [Gradle](https://gradle.org/) - for building the project
* [Google Protocol Buffers](https://github.com/google/protobuf) - for use with serialization and hardware communications

### Getting started

To get started, it is best to have the latest JDK and Gradle installed. The HEAD of the `master` branch contains the latest development code and various production releases are provided on feature branches.

#### Building from the command line

Official builds are currently using JDK 11. Our GitHub Actions build and test with JDK 11 and JDK 17.

To perform a full build (*including* JavaDocs and unit/integration *tests*) use JDK 11+.
```
gradle clean build
```
If you are using Gradle 4.10 or later, the build will automatically include the JavaFX-based `wallettemplate` module. The outputs are under the `build` directory.

To perform a full build *without* unit/integration *tests* use:
```
gradle clean assemble
```

#### Building from an IDE

Alternatively, just import the project using your IDE. [IntelliJ](http://www.jetbrains.com/idea/download/) has Gradle integration built-in and has a free Community Edition. Simply use `File | New | Project from Existing Sources` and locate the `build.gradle` in the root of the cloned project source tree.

### Building and Using the Wallet Tool

The **bitcoinj** `wallettool` subproject includes a command-line Wallet Tool (`wallet-tool`) that can be used to create and manage **bitcoinj**-based wallets (both the HD keychain and SPV blockchain state.) Using `wallet-tool` on Bitcoin's test net is a great way to learn about Bitcoin and **bitcoinj**.

To build an executable shell script that runs the command-line Wallet Tool, use:
```
gradle bitcoinj-wallettool:installDist
```

You can now run the `wallet-tool` without parameters to get help on its operation:
```
./wallettool/build/install/wallet-tool/bin/wallet-tool
```

To create a test net wallet file in `~/bitcoinj/bitcoinj-test.wallet`, you would use:
```
mkdir ~/bitcoinj
```
```
./wallettool/build/install/wallet-tool/bin/wallet-tool --net=TEST --wallet=$HOME/bitcoinj/bitcoinj-test.wallet create
```

To sync the newly created wallet in `~/bitcoinj/bitcoinj-test.wallet` with the test net, you would use:
```
./wallettool/build/install/wallet-tool/bin/wallet-tool --net=TEST --wallet=$HOME/bitcoinj/bitcoinj-test.wallet sync
```

To dump the state of the wallet in `~/bitcoinj/bitcoinj-test.wallet` with the test net, you would use:
```
./wallettool/build/install/wallet-tool/bin/wallet-tool --net=TEST --wallet=$HOME/bitcoinj/bitcoinj-test.wallet dump
```

Note: These instructions are for macOS/Linux, for Windows use the `wallettool/build/install/wallet-tool/bin/wallet-tool.bat` batch file with the equivalent Windows command-line commands and options.

### Example applications

These are found in the `examples` module.

### Where next?

Now you are ready to [follow the tutorial](https://bitcoinj.github.io/getting-started).

### Testing a SNAPSHOT build

Building apps with official releases of **bitcoinj** is covered in the [tutorial](https://bitcoinj.github.io/getting-started).

If you want to develop or test your app with a [Jitpack](https://jitpack.io)-powered build of the latest `master` or `release-0.15` branch of **bitcoinj** follow the dynamically-generated instructions for that branch by following the correct link.


* [master](https://jitpack.io/#bitcoinj/bitcoinj/master-SNAPSHOT) branch
* [release-0.15](https://jitpack.io/#bitcoinj/bitcoinj/release-0.15-SNAPSHOT) branch