Adding the JreEmulation Project to Your Xcode Project

J2ObjC's JRE emulation library can be built using Xcode, and can be included as a sub-project in your Xcode projects. This allows you to control the settings used to build that library so it can best be used by your projects.

Download the Source Code

Either: - Download and upzip the current source bundle into a local directory; or - Clone the source code tree using git. The advantage of a local source check out is that it's easier to stay current with the latest J2ObjC project changes, but it does require some knowledge of version control systems.

The source code can go anywhere on your local system. For the purposes of this document we'll use /usr/local/src/j2objc, but change that path as you prefer.

Install Build Tools

Xcode's command-line tools and Apache Maven need to be installed to build J2ObjC. Here are some tips:

These are Google searches instead of static pages, because installation can often change with new Mac OS X and Xcode versions.

Build the Project

Follow the Building J2ObjC steps. Command-line builds are optional, but easier to debug than when invoked inside Xcode.

When debugging the JRE, it is recommended to add the following lines at the top of the jre_emul/ before running a clean build:


The JreEmulation Xcode project

In Xcode, open /usr/local/src/j2objc/jre_emul/JreEmulation.xcodeproj. Its folders include:

  • Classes: the set of core JRE emulation classes, which are not created by translating Java source files.
  • jre_emul_tests: the set of unit tests which are built and run within Xcode. These do not include the translated JUnit tests, which are built and run from the command-line using make test in the jre_emul directory.
  • Transpiled Classes: these are the files created by translating the JRE library's Java source files. Notes:
  • Xcode marks missing files in red. Because these files are created during the build, they will initially all be red until the project is built.
  • We're adding new classes regularly to the JRE emulation library, so this list may be out of date. If so, right-click on this folder, click "Add Files to JreEmulation.xcodeproj", and add new .m and .h files from jre_emul/build_result/Classes and its sub-directories.

To build the JreEmulation project, select the jre_emul target and click Xcode's Run button. To build and run the unit tests, click on the down arrow next to the Run button and select Test.

Add the JreEmulation project to your project

  • In the Project Naviagator panel on the left, right-click on your project and select "Add Files to Project Name".
  • Find the jre_emul/JreEmulation.xcodeproj file and click the Add button.
  • Click your project and select its main target, then select the target's Build Phases tab.
  • Open the Target Dependencies section, click the + button, and select the jre_emul target.
  • Open the Link Binary With Libraries section, click the + button, and select libjre_emul.a.
  • Select the target's Build Settings tab, find Header Search Paths, and add the path to the /usr/local/src/j2objc/dist/include directory (substituting the actual location).

Now when your project is built, the JreEmulation project is built as needed.