How do I add a java gradle submodule to my Android module? - java

Suppose I have an Android application project in IntelliJ Idea with Gradle. Call it MyApplication.
What I want to do is to add a plain java library module (not Android library project) as a submodule to MyApplication. Lets call this module a testlib.
And then when whole project is built, I want this module compiled to jar and included to /libs folder of MyApplication.
What I tried: I've created a submodule testlib and included it as a dependency to MyApplication, but I get a following warning:
Warning:Gradle: module 'testlib' won't be compiled. Unfortunately you
can't have non-Gradle Java module and Android-Gradle module in one
project.
Is this even possible?

If you've created your project in IntelliJ as an Android-gradle project, then when you go to the "Add new module" window you should see an "Gradle: Java library" option like this:

IntelliJ IDEA does not support Gradle and Non-Gradle modules in one single project. A comment from JetBrains in their forum states this clearly.
The solution is to either convert the Maven modules into Gradle
modules or split the project in two. With the latter approach, if you
build the plain java library module with Maven before building the
Gradle project, you will still be able to use it as a dependency in
the Android application project.
Beware of using different Java language source levels in multi-module
Gradle projects. IntelliJ IDEA does not handle them correctly due to a
bug in either IntelliJ IDEA or Gradle. (There is a pending discussion
whether this should be fixed in the IDE or Gradle.)

Related

Export Maven project with subproject to jar-file

I'm writing a lot of plugins for minecraft bukkit server's and I've grown tired of copy+pasting the same utility classes in my projects all over again. I decided to just put them all in a separate project and add them to my plugins via maven. I'm using IntelliJ Ultimate.
I want to have a maven project that contains all my utitily classes called e.g. UtilityAPI. Then I want to be able to create another project, which will be my bukkit plugin. In this second project I want to be able to use all the code from the first one. Also, I'd like it very much, that if I choose to build a plugin jar, maven automatically takes into account the most recent code from my API-Project.
I started working on this and started reading about maven modules and how you can use them to forge different projects together. I initially thought, that this was just what I needed, and tried to just add
<modules>
<module>UtilityAPI</module>
</modules>
However this results in my bukkit plugin project being considered a parent project, and refuses to build in a jar, but just in a (at least for me) rather useless .pom file. I'm not sure how to proceed. Do I have to create a "parent" project for my bukkit plugin project which contains the api and the plugin project as modules? And if yes, how do I generate a .jar, and not a .pom?
The dream solution would be to have the UtilityAPI project, and being able to include it in any new plugins that I might write in the future. I'd also be a fan of having a simple way to create a jar with the newest sources of my plugin in it. Is this possible, and if yes, how?
In your Maven multi-module project your plugin would have to be another module (and not the parent, which has packaging type pom). This module would then have a dependency on the API module (dependencies between modules are possible).
However, multi-module projects are usually intended for projects which are tightly coupled. That does not appear to be the case for your scenario. It sounds like the plugins have (potentially) nothing in common except for the dependency on the API project. Maybe it would be better to have the API project as separate standalone Maven project and then deploy snapshot versions of it (or install them only to your local Maven repository) and use these in your plugin projects.

Eclipse: reference local code instead of cached gradle dependency

I have two gradle java projects imported into Eclipse, one being a dependency of the other.
I would like for Eclipse to use the local dependency code, instead of the compiled dependency in the gradle cache folders, so I can modify and debug both projects simultaneously.
How do I force Eclipse to use a local dependency code?
The feature you are referring to is known as Composite Builds:
Importing into the IDE
One of the most useful features of composite builds is IDE integration. By applying the idea or eclipse plugin to your build, it is possible to generate a single IDEA or Eclipse project that permits all builds in the composite to be developed together.
In addition to these Gradle plugins, recent versions of IntelliJ IDEA and Eclipse Buildship support direct import of a composite build.
Importing a composite build permits sources from separate Gradle builds to be easily developed together. For every included build, each sub-project is included as an IDEA Module or Eclipse Project. Source dependencies are configured, providing cross-build navigation and refactoring.
The most simple way of achieving this is to use includeBuild in your settings.gradle.
rootProject.name = 'my-composite'
includeBuild 'my-app'
includeBuild 'my-utils'
With that in place, there's no need to configure the build path manually in Eclipse.
Gosh this was a trivial one and it took me way too long to figure it out.
Solved the issue by creating a file named external-projects.properties in the root folder of the parent project with the relative or full path to the dependency project folder.
To be precise, for me the folders tree ends up like this:
git-folder/
|__parent-project/
|__external-projects.properties
|__build.gradle.kts
|__rest (src/main, etc)
|__dependency-project/
|__build.gradle.kts
|__rest (src/main, etc)
And the contents of the external-projects.properties file:
dependency-project = ../dependency-project
The dependency project must also be in the build path of the parent project (done by "Right-Click project > Build Path > Configure Build Path" and adding it in the "Projects" tab).
After that, a "Right Click > Gradle > Refresh Gradle Project" did the trick.

Include another project using Gradle? [duplicate]

I created a library project in Android Studio (currently 0.5.2) by choosing File > New Project... > "Mark this project as a library".
I have two other non-library projects that I would like to add a dependency to this library project.
-My Library
-Project 1 (depends on My Library)
-Project 2 (depends on My Library)
My goal is to keep each project independent and avoid duplicating modules/code. How can this be done without copying the library module into the other projects?
Update:
Android Studio 0.6.0 allows you to Import a module, though, this simply copies the module source into the Project.
You can also refer to a library outside of your project folder using the project().projectDir property. If your external library is relative to your project like so
- MyLibrary
- library
- MyProject
- app
in MyProject/settings.gradle
include ':library'
project(':library').projectDir = new File(settingsDir, '../MyLibrary/library')
in MyProject/app/build.gradle
dependencies {
compile project(':library')
}
This is very similar to this question:
Sharing an Android library between multiple Android apps using Gradle
Instead of pushing to maven central you can push to your local maven repository (mavenLocal() in build.gradle)
Another route (if you don't want to deploy the library somewhere) is to use your VCS and check out the library within your project. Git has submodules for that, Mercurial has subrepos and SVN has external to name a few examples.
Then add it to your Gradle build using a project dependency.

I just started learning Maven. How does Eclipse build without it?

I've been coding Java in Eclipse for awhile without needing to specify dependencies. Now that I learned how Maven does it, I'm wondering: how did Eclipse build projects on its own? How did Eclipse figure out which versions of imports, and which dependencies of dependencies, are needed to make everything work?
Finally, what are the advantages and disadvantages of building a project in Eclipse by starting with New->Other->Maven Project instead of New->Java Project?
To the first question: Eclipse doesn't add any dependency in a standard Java project. You have to manually add to the Build Path all needed JARs, otherwise you'll have compilation errors.
To the second question: if you create a standard Java project Maven is not used, even if you create a pom.xml file in the root of the project. You can always convert a standard Java project in a Maven project (see Convert Existing Eclipse Project to Maven Project).
Your dependencies has always to be in the classpath
When you start a project with Maven, Eclipse will automatically add the Maven repository to the classpath.
When you start a Java project you have to link your library manually in Eclipse and the version of the library is the one you've downloaded.
You can see the difference in your project's Properties > Java Build Path > Libraries

How to add Spring jars to Java Project mirroring folder in git repo

Long title, but pretty much explains it. I've pulled a git repo (spring rest tutorial http://spring.io/guides/tutorials/rest/) which contains multiple standalone java projects each in separate folders. Each of these projects contains gradle build files as well as gradle itself (no need to install gradle), AND the necessary Spring jars (likely in the gradle-wrapper jar). I've created a java project in eclipse that mirrors one of the folders and the changes in eclipse are picked up no problem and it builds fine.
The problem I have is that the Spring dependencies aren't on the Eclipse build path, so I can't use all of the nice Eclipse features (function completion, auto imports, etc.). There's only one jar in each separate folder from the git repo and it's called gradle-wrapper.jar. My guess is that this contains all the Spring dependencies, as the project builds fine, assuming I've typed everything correctly and manually added correct import statements.
Is there a way to set this up so that I'm not getting all these ugly errors in the java project? I attempted to add the gradle jar to the java project build path, but this had no effect. I suppose one option would be to add the spring dependencies separately, but then the Spring on the build path wouldn't necessarily match the Spring dependencies used by gradle for the actual build.
Gradle projects don't package all the dependencies in the repository; one of the primary reasons to use Gradle or Maven is that they'll handle dependencies for you. You need the Gradle Eclipse plugin and to Import->Existing Gradle projects.

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