Project status: Private beta. Expect minor bugs and API changes. Not suitable for production, but early adopter developers and early testers should get on board.
MultiBit HD (MBHD)
A desktop Hierarchical Deterministic Wallet (HDW) for Bitcoin using the Simplified Payment Verification (SPV) mode to provide very fast blockchain synchronization.
The target audience is "international mainstream" which compels the user interface to remain as simple and consistent as possible while still retaining advanced capabilities under the covers.
Support for external hardware wallets (such as the Trezor) is available through the MultiBit Hardware project.
- Java 7 and Swing
- Bitcoinj - Providing various Bitcoin protocol utilities (GitHub is the reference)
- Java HID API - Java library providing USB Human Interface Device (HID) native interface
- Google Protocol Buffers (protobuf) - For use with serialization and hardware communications
- Font Awesome - for iconography
- JWrapper - for a smooth installation and update process
MultiBit HD is a standard Maven build, but currently relies on some snapshot builds of libraries which aren't available in Maven Central.
Verify you have Maven 3+
IDEs such as Eclipse may require the m2eclipse plugin to be configured.
To quickly check that you have Maven 3+ installed check on the command line:
$ mvn --version
We currently use a forked version of Bitcoinj
The MultiBit Staging repository contains a
and supporting Orchid JAR for TOR that is aligned with the MultiBit HD
develop branch. This should be used for
development builds and is suitable for production. As we make changes to our fork we update the staging repository.
Wherever possible we will introduce our forked changes as a pull request into the upstream bitcoinj so that other projects can benefit but we must use a fork to ensure rapid updates are possible during development.
Start the application (from an IDE)
To run the application within an IDE, simply execute
MultiBitHD.main() in the
mbhd-swing module. No command line parameters are needed, although a Bitcoin URI is accepted.
Start the application (from the command line)
To run the application from the command line, first build from the project root directory:
$ mvn clean install
then start the application using the shaded JAR:
$ java -jar mbhd-swing/target/multibit-hd.jar
No command line parameters are needed, although a Bitcoin URI is accepted (the quotes are required to avoid URL decoding):
$ java -jar mbhd-swing/target/multibit-hd.jar "bitcoin:1AhN6rPdrMuKBGFDKR1k9A8SCLYaNgXhty?amount=0.01&label=Please%20donate%20to%20multibit.org"
MultiBit HD will avoid multiple instances by using port 8330 as a method of detecting another running instance. If port 8330 cannot be bound MultiBit HD will assume that another instance is running and hand over any Bitcoin URI arguments present when it started. It will then perform a hard shutdown terminating its own JVM. The other instance will react to receiving a Bitcoin URI message on port 8330 by displaying an alert bar requesting the user to act upon the Bitcoin URI payment request.
Frequently asked questions (FAQ)
Here are some common questions that developers ask when they first encounter MBHD.
How can I contribute ?
Simply add yourself as a watcher to the repository and keep and eye on issues that interest you.
In general issues are labelled with a yellow
awaiting review or a blue
in progress to indicate where our attention is focused. We would appreciate you updating and running up
the code and verifying that an
awaiting review does what it is supposed to. If you could then post a comment similar to
Works for me on Linux then that would help us to close
off the issue faster, or engage further with it to get bugs fixed.
Of course, if you want to contribute coding effort or deeper code review and commentary that would be most appreciated as well. We want MultiBit HD to be as solid as we can make it.
As always, donations to the MultiBit address are welcome: 1AhN6rPdrMuKBGFDKR1k9A8SCLYaNgXhty.
Where's the Trezor support ?
We've begun the process of integrating the Trezor device through the MultiBit Hardware project. If you are a hardware wallet developer, or are just interested to learn how the Trezor device works under the covers please watch this project.
From now you should be able to attach your Trezor device and see an alert message providing information and a button to switch your current wallet over to one that tracks your Trezor device. All private keys remain on the Trezor device and associated contacts, payments and so on are keep encrypted in your wallet.
Why not Java 8 ?
At the time MBHD was being written (Q4 2013 - Q2 2014) Java 8 was not in production release and the sheer size of the packaged download was coming in at 150Mb (18x MultiBit Classic and 3x the standard Java 7 packaged footprints). That footprint alone would be sufficient to dramatically increase the cost of serving the application and deter people from downloading in countries where bandwidth is less available.
We will revisit this once we have suitable compressed JWrapper JREs available.
Why not JavaFX ?
JavaFX was only available as version 2.2 on Java 7 and the move to Java 8 was not going to happen. There were many significant features missing in JavaFX 2.2 which would only be fixed in Java 8:
- no right to left languages (Hebrew, Farsi, Arabic, etc)
- no integration with native platform for Bitcoin URI protocol handling
- no reporting uncaught exceptions
Thus this technology was not suitable for the very wide range of people using MultiBit in all corners of the globe.
Why Swing ?
There is a vast amount of support for Swing. The code is near bullet-proof for most use cases and it fully supports internationalization which is a key requirement for MultiBit HD. Also, many of the supporting libraries for Swing pre-date 2009 making it much harder for dependency chain attacks to take place.
With some effort Swing can be made to look quite modern.
Swing also allows us to smoothly integrate with the native platform which puts it ahead of JavaFX until at least Q4 2014.
Why not SwingX ?
SwingX is a large support library that introduces a lot of additional functionality to Swing applications. Much of this additional functionality is not required by MultiBit or can be relatively easily worked around. Consequently including it would increase the available attack surface.
Why the Nimbus look and feel ?
In Java 7 the Nimbus look and feel became integrated with the JDK. It provides a modern 2D rendered UI that is the same across all platforms. It is highly customisable through simple themes and provides consistent painting behaviour across platforms. For example to paint a button red in Swing using the Mac-only Aqua theme requires complex custom ButtonUI code.
Using Nimbus ensures that we don't have this or similar problems.
I want an installer not this IDE
Installers lag the latest changes by a few weeks. You can find them on the MultiBit HD website.
As new changes are released they will update automatically from 0.0.4 (Private Beta 4) onwards.
Is there a developer wiki ?
Yes. The wiki pages provide comprehensive instructions for developers that cover a variety of environments.
What is your development roadmap ?
We are currently working to the following timetable:
- Hardware wallet (Trezor) support (see version 0.0.5 issues)
- BIP70-73 payment protocol support (see version 0.1.0 issues)
- Webcam support (see version 0.2.0 issues)
- Hierarchical deterministic multi-signature (HDM) support (still planning)
This section covers tools to assist developers when developing MBHD code.
Executing the automated requirements tests
We use Swing FEST to perform automated requirements testing of the user interface. It gives super fast overview of the
application and runs like a standard unit test.
MultiBitHDFestTest provides the entry point.
This provides an ever-improving set of regression tests to ensure that new code does not break the existing work.
The code is arranged as a single test case with multiple individual tests that are independent of each other. Each create their own temporary application directory and may or may not require an initial randomly created empty wallet.
Developers are strongly encouraged to create a FEST test for any UI work they are about to undertake and use it to actually test the work in progress. It is far faster to run FEST than to manually run up the application and do it manually.
FEST is not intended to run as part of a Maven build since not all build environments support a display.
Upgrading Font Awesome
FontAwesomeTools to create the necessary enum entries for
AwesomeIcon as required.
Changing resource bundles
ResourceBundleTools to find similar entries and to arrange keys in the same order across all bundles.
Updating the internal help files
To do an internal help refresh:
- Ensure you have cloned the MultiBit website into a sibling directory to MultiBit HD
- Switch to the appropriate site branch (e.g.
masterfor ongoing releases) and update
- Use Ant to execute the
update-internal-help.xmlscript to copy the relevant files into the correct locations
- Within Intellij, navigate to
assets/images/en/screenshots/mbhd-01, select all image files and copy to clipboard
- Paste image names into
HelpScreenViewwhere directed (remove existing)
- Update any FEST tests that rely on particular text being in place
- Run without a network connection to verify that the internal help appears correctly
- Check internal and external links work correctly
- Check IDE Changes to ensure no new files have been missed
Updating the internationalisation files
To do an i18n refresh:
- Download the i18n zip using the Download button
- Unzip this to a directory
- Run a terminal and cd to
- Run the script
This moves and renames all the files into the languages directory.
If there are any files or new languages it lists them at the end so that you can see there is something missing from the