Using Intellij IDEA for Mod-Development with ForgeGradle

[diesieben07]

Note (Sep. 2017): This post is now getting very old, but it still applies. Regardless you might want to refer to the IntelliJ section in the official Getting Started guide instead.

 

In this Tutorial I will describe how you can use the Intellij IDEA IDE for Mod-Development.

 

First, you are going to need to download the Mod Development Kit ("MDK") package from http://files.minecraftforge.net/ ("src" for old versions) and unzip it.

 

Next, start up Intellij. If you already have a Project opened, select File > Open, otherwise select "Open Project". Navigate to the directory where you unzipped Forge to and select the build.gradle file. Leave the import-settings at default and click OK.

Intellij will now take a while to import the project. Once that's done, open the Gradle-sidebar.

If the sidebar is not visible, click the view-switcher in the bottom-left corner:

 

Select the setupDecompWorkspace task from the list and run it (double-click). If you don't need the Minecraft source code visible, run setupDevWorkspace instead, it will be faster.

Once the task has finished, click the Refresh button in the Gradle-sidebar. That will again take a moment. Once Intellij has finished refreshing, your project is already almost ready to go. You should be able to see all the libraries used by Forge & Minecraft on the left and also the source code for the ExampleMod inside src/main/java.

 

All that is left to do are the run configurations, so that you can actually start Minecraft. For those again open the Gradle sidebar and run the genIntellijRuns task. Intellij might ask to reload the project, click OK if it does.

 

If your run configurations show an error in most recent versions of IntelliJ you have to go into Run > Edit Configurations and adjust both run configurations like shown below.

 

That's it!

Edited September 14, 2017 by diesieben07
Updated for new forum and new ForgeGradle / IntelliJ versions

[McJty]

I followed this and discovered this problem when trying to run the client:

 

/usr/lib/jvm/java-7-oracle/bin/java -Xincgc -Xmx1024M -Xms1024M -Djava.library.path=/home/jorrit/mc/forge_1.7.10_src/build/natives -Dfml.ignoreInvalidMinecraftCertificates=true -Didea.launcher.port=7533 -Didea.launcher.bin.path=/home/jorrit/idea-IC-135.909/bin -Dfile.encoding=UTF-8 -classpath /usr/lib/jvm/java-7-oracle/jre/lib/deploy.jar:/usr/lib/jvm/java-7-oracle/jre/lib/charsets.jar:/usr/lib/jvm/java-7-oracle/jre/lib/jce.jar:/usr/lib/jvm/java-7-oracle/jre/lib/management-agent.jar:/usr/lib/jvm/java-7-oracle/jre/lib/plugin.jar:/usr/lib/jvm/java-7-oracle/jre/lib/javaws.jar:/usr/lib/jvm/java-7-oracle/jre/lib/resources.jar:/usr/lib/jvm/java-7-oracle/jre/lib/rt.jar:/usr/lib/jvm/java-7-oracle/jre/lib/jfr.jar:/usr/lib/jvm/java-7-oracle/jre/lib/jfxrt.jar:/usr/lib/jvm/java-7-oracle/jre/lib/jsse.jar:/usr/lib/jvm/java-7-oracle/jre/lib/ext/zipfs.jar:/usr/lib/jvm/java-7-oracle/jre/lib/ext/localedata.jar:/usr/lib/jvm/java-7-oracle/jre/lib/ext/sunpkcs11.jar:/usr/lib/jvm/java-7-oracle/jre/lib/ext/dnsns.jar:/usr/lib/jvm/java-7-oracle/jre/lib/ext/sunec.jar:/usr/lib/jvm/java-7-oracle/jre/lib/ext/sunjce_provider.jar:/home/jorrit/mc/forge_1.7.10_src/classes/production/forge_1.7.10_src:/home/jorrit/.gradle/caches/minecraft/net/minecraftforge/forge/1.7.10-10.13.0.1186/start:/home/jorrit/.gradle/caches/minecraft/net/minecraftforge/forge/1.7.10-10.13.0.1186/forgeSrc-1.7.10-10.13.0.1186.jar:/home/jorrit/.gradle/caches/modules-2/files-2.1/net.minecraft/launchwrapper/1.9/116f2aad5b0c68353ebed66cd463517db6522f7e/launchwrapper-1.9.jar:/home/jorrit/.gradle/caches/modules-2/files-2.1/org.ow2.asm/asm-debug-all/4.1/dd6ba5c392d4102458494e29f54f70ac534ec2a2/asm-debug-all-4.1.jar:/home/jorrit/.gradle/caches/modules-2/files-2.1/com.typesafe.akka/akka-actor_2.11/2.3.3/ed62e9fc709ca0f2ff1a3220daa8b70a2870078e/akka-actor_2.11-2.3.3.jar:/home/jorrit/.gradle/caches/modules-2/files-2.1/com.typesafe/config/1.2.1/f771f71fdae3df231bcd54d5ca2d57f0bf93f467/config-1.2.1.jar:/home/jorrit/.gradle/caches/modules-2/files-2.1/org.scala-lang/scala-actors-migration_2.11/1.1.0/dfa8bc42b181d5b9f1a5dd147f8ae308b893eb6f/scala-actors-migration_2.11-1.1.0.jar:/home/jorrit/.gradle/caches/modules-2/files-2.1/org.scala-lang/scala-compiler/2.11.1/56ea2e6c025e0821f28d73ca271218b8dd04926a/scala-compiler-2.11.1.jar:/home/jorrit/.gradle/caches/modules-2/files-2.1/org.scala-lang.plugins/scala-continuations-library_2.11/1.0.2/e517c53a7e9acd6b1668c5a35eccbaa3bab9aac/scala-continuations-library_2.11-1.0.2.jar:/home/jorrit/.gradle/caches/modules-2/files-2.1/org.scala-lang.plugins/scala-continuations-plugin_2.11.1/1.0.2/f361a3283452c57fa30c1ee69448995de23c60f7/scala-continuations-plugin_2.11.1-1.0.2.jar:/home/jorrit/.gradle/caches/modules-2/files-2.1/org.scala-lang/scala-library/2.11.1/e11da23da3eabab9f4777b9220e60d44c1aab6a/scala-library-2.11.1.jar:/home/jorrit/.gradle/caches/modules-2/files-2.1/org.scala-lang.modules/scala-parser-combinators_2.11/1.0.1/f05d7345bf5a58924f2837c6c1f4d73a938e1ff0/scala-parser-combinators_2.11-1.0.1.jar:/home/jorrit/.gradle/caches/modules-2/files-2.1/org.scala-lang/scala-reflect/2.11.1/6580347e61cc7f8e802941e7fde40fa83b8badeb/scala-reflect-2.11.1.jar:/home/jorrit/.gradle/caches/modules-2/files-2.1/org.scala-lang/scala-swing_2.11/1.0.1/b1cdd92bd47b1e1837139c1c53020e86bb9112ae/scala-swing_2.11-1.0.1.jar:/home/jorrit/.gradle/caches/modules-2/files-2.1/org.scala-lang.modules/scala-xml_2.11/1.0.2/820fbca7e524b530fdadc594c39d49a21ea0337e/scala-xml_2.11-1.0.2.jar:/home/jorrit/.gradle/caches/modules-2/files-2.1/net.sf.jopt-simple/jopt-simple/4.5/6065cc95c661255349c1d0756657be17c29a4fd3/jopt-simple-4.5.jar:/home/jorrit/.gradle/caches/modules-2/files-2.1/lzma/lzma/0.0.1/521616dc7487b42bef0e803bd2fa3faf668101d7/lzma-0.0.1.jar:/home/jorrit/.gradle/caches/modules-2/files-2.1/com.mojang/realms/1.3.1/f78f5a841b1cf9d50c3382acdbeb7d3078e454d6/realms-1.3.1.jar:/home/jorrit/.gradle/caches/modules-2/files-2.1/org.apache.commons/commons-compress/1.8.1/a698750c16740fd5b3871425f4cb3bbaa87f529d/commons-compress-1.8.1.jar:/home/jorrit/.gradle/caches/modules-2/files-2.1/org.apache.httpcomponents/httpclient/4.3.3/18f4247ff4572a074444572cee34647c43e7c9c7/httpclient-4.3.3.jar:/home/jorrit/.gradle/caches/modules-2/files-2.1/commons-logging/commons-logging/1.1.3/f6f66e966c70a83ffbdb6f17a0919eaf7c8aca7f/commons-logging-1.1.3.jar:/home/jorrit/.gradle/caches/modules-2/files-2.1/org.apache.httpcomponents/httpcore/4.3.2/31fbbff1ddbf98f3aa7377c94d33b0447c646b6e/httpcore-4.3.2.jar:/home/jorrit/.gradle/caches/modules-2/files-2.1/java3d/vecmath/1.3.1/a0ae4f51da409fa0c20fa0ca59e6bbc9413ae71d/vecmath-1.3.1.jar:/home/jorrit/.gradle/caches/modules-2/files-2.1/net.sf.trove4j/trove4j/3.0.3/42ccaf4761f0dfdfa805c9e340d99a755907e2dd/trove4j-3.0.3.jar:/home/jorrit/.gradle/caches/modules-2/files-2.1/com.ibm.icu/icu4j-core-mojang/51.2/63d216a9311cca6be337c1e458e587f99d382b84/icu4j-core-mojang-51.2.jar:/home/jorrit/.gradle/caches/modules-2/files-2.1/com.paulscode/codecjorbis/20101023/c73b5636faf089d9f00e8732a829577de25237ee/codecjorbis-20101023.jar:/home/jorrit/.gradle/caches/modules-2/files-2.1/com.paulscode/codecwav/20101023/12f031cfe88fef5c1dd36c563c0a3a69bd7261da/codecwav-20101023.jar:/home/jorrit/.gradle/caches/modules-2/files-2.1/com.paulscode/libraryjavasound/20101123/5c5e304366f75f9e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com.intellij.rt.execution.application.AppMain GradleStart
[19:40:19] [main/INFO] [GradleStart]: No arguments specified, assuming client.
[19:40:19] [main/INFO] [GradleStart]: Extra: []
Exception in thread "main" java.lang.RuntimeException: java.io.FileNotFoundException: /home/jorrit/.gradle/caches/minecraft/assets/indexes/{ASSET_INDEX}.json (No such file or directory)
at com.google.common.base.Throwables.propagate(Throwables.java:160)
at GradleStart.setupAssets(GradleStart.java:274)
at GradleStart.startClient(GradleStart.java:82)
at GradleStart.main(GradleStart.java:56)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:134)
Caused by: java.io.FileNotFoundException: /home/jorrit/.gradle/caches/minecraft/assets/indexes/{ASSET_INDEX}.json (No such file or directory)
at java.io.FileInputStream.open(Native Method)
at java.io.FileInputStream.<init>(FileInputStream.java:146)
at java.io.FileReader.<init>(FileReader.java:72)
at GradleStart.loadAssetsIndex(GradleStart.java:280)
at GradleStart.setupAssets(GradleStart.java:218)
... 7 more

Process finished with exit code 1

 

Anything I missed?

[diesieben07]

I am not sure what causes this. For me the fix is to close idea, open the console (cmd) and run setupDecompWorkspace again from there (with --refresh-dependencies).

[McJty]

Actually that works! Thanks a lot. Now I need to make my very first mod :-)

 

I do have another question though. Now to add my own mod I suppose I need to make a module? I did that and copied the example mod code from forge. Added Forge dependencies and it compiles fine. However, how can I change my run configuration to actually add my mod when I run MC?

 

Thanks!

[diesieben07]

No! Don't make a module! All you need to do is create your files inside src/main/java.

[McJty]

Thanks, now it works and I created my very first mod which does absolutely nothing at all :-)

[McJty]

I'm a bit confused on how to setup IntelliJ/gradle and github so that I can have a github repository with several mods (each with source and assets) and how to integrade that into the src/main/java dirs and src/main/resources. Is there a good guide on how to set that up with MC and IntelliJ in mind?

 

That's initially why I thought of using modules so that every module could have its own github directory but now it seems that I have to split assets and source?

 

Thanks,

[diesieben07]

You would have a separate repo for every mod. And a separate IDEA project for every mod.

[McJty]

Hmm, doesn't that take up a lot of disk space? Seems not very handy to work like that. Especially if the mods are supposed to work together. Also that still doesn't solve how I can get the separate 'src/main/java' and 'src/main/resources' into a single github repository?

[diesieben07]

Why do you want a single repository? That makes no sense. One Repo per mod.

And no, it does not take up a lot of disk space. All the dependencies (including forge, minecraft and their sourcecode) is stored in a central location, thanks to gradle. Even if you have 100 workspaces using the same forge version, you will only get one jar file containing forge, which is used by all workspaces.

[McJty]

Yes I mean one repo for one mod. But the problem is that that repo should contain both the source and the assets dir. But the build dir contains separate src and resource folders. How do I map the folders on my HD to the single repository on github?

[diesieben07]

I am not sure what you mean. Your repo should contain both, of course. For that just make the repo in the root, where your build.gradle is. A typical repo then looks like this: https://github.com/diesieben07/SevenCommons

[McJty]

Ok, but that example doesn't seem to have any resources/assets. And that's my problem. With the actual mod it has to be called 'assets' but it is called 'resources' in the project that I created. I guess I'm a bit confused how I could get my assets in the correct place in the github repository.

 

Ah oops! Missed the resources inside the main folder. Sorry!

[diesieben07]

The github repo looks exactly like your workspace on your computer.

Assets in src/main/resources, java files in src/main/java.

And yes, the mod I linked has assets: https://github.com/diesieben07/SevenCommons/blob/master/src/main/resources/assets/sevencommons/gui.png

[Digital_Light]

I got to the setupDevWorkspace and it returned

(The filename, directory name, or volume label syntax is incorrect)

i am setting up for 1.7.10.

[diesieben07]

What is the full path to your forge workspace? Did you run setupDevWorkspace from inside IDEA?

[Ives]

Hey!

I'm trying to add javadocs to Forge but haven't succeeded yet. Is there a way to add javadocs to Forge?

[diesieben07]

If you run setupDecompWorkspace you'll get the sources, which include the Javadoc.

[GamrCorps]

I copied the code exactly in the tutorial but my Minecraft Client will not load my mod anymore. Anyone know how to fix that?

[diesieben07]

Are there any issues in your console?

[GamrCorps]

No errors or anything, it seems like the classes are just not being made or transferred properly. I use the exact code above too.

[diesieben07]

Is your mod in src/main/java? Is that folder marked as "sources root"?

[GamrCorps]

where would I check if it is marked as sources root? And it is in src/main/java

 

EDIT: Nevermind I found it, it is marked as the sources root.

[GamrCorps]

I have absolutely no clue how I fixed the problem, but I somehow did. Thanks for the support.

[Player131]

I'm trying to rebuild everything on IntelliJ IDEA 14.0 Ultimate (Yes i bought it). But it gives a crash when adding your fix for assets : Error:(1,0) Gradle DSL method not found: 'sourceSets()', is that normal ?

 

After second problem, when i arrive to rebuild the workspace without the crashing line of code (sourceSets thing), my game launches, forge find my mod, but no assets can be compiled, i tried everything and nothing works. The only way i found is forcing resource building by copying folders myself on the classes output folder.

 

 

EDIT : Ok, it's working now, just needed to add the spetial line of code after the rest of the file build.gradle