Java sources replaced by decompiled files in Intellij

Question

When I'm opening a specific class using ctrl + right click I should be redirected to a window with the java sources which contains all the lines and the appropriate comments. But instead I get a window with the decompiled .class file.

I have tried to deactivate the decompiler plugin but it does not work.

If I add http://docs.oracle.com/javase/8/docs/api to Project Structure -> SDKs -> Documentation Paths I can get an overview of the class or method's I'm rolling over, but still can't open the right source file.

Any ideas?

Wandy

I don't think you are seeing the decompiled class files but rather placeholders. I think you need to attach sources. Maven projects in IntelliJ do this automatically AFAIK. – Bluejacket

Maven's "Automatically download" sources/documentation are both checked – Wandy

Answer 1

When navigting to sources, IDEA will first go to attached sources. If not present, it will decompile the class and display it.

Try the following troubleshooting to track down the issue:

1. Make sure the sources are properly attached.

For libraries, Open the Project Structure dialog (Ctrl+Alt+Shift+S or ⌘;) and select "Libraries" on the left under "Project Settings". Find the library in question, and select it. It will show if the source is attached. You mentioned you have Maven's "Automatically download" sources/documentation both checked. So for any maven libraries that have source available, it should be listed.

If it is not listed or is in red, run "Download Sources" or "Download Sources and Documentation" from the Maven tool window. If the source is till in red, it likely means it is not available for that artifact in the maven repository. Use Maven Search to verify such.

For the JDK, select "SDKs" in the Project Structure dialog, find the JDK, and then select the "Sourcepath" tab. Make sure the {jdk-home}/src.zip file is listed.

IDEA should automatically set this when you add the JDK, but if not, add it.

2. Make sure the source JAR/ZIP file is not corrupt

Navigate to the archive in explorer/finder and make sure it can be opened and viewed.

3. Refresh IDEA's Caches

It's possible that IDEA's caches/indexes are corrupted. As such, IDEA is not "seeing" the link between the class and the source code. Go to File > Invalidate Caches / Restart...". Invalidate the caches and restart IDEA. Wait for IDEA to finish re-indexing the project and libraries (watch the progress in the bottom right of the IDEA window).

One of the above should resolve the issue.

FYI, If you do not want IDEA to decompile code(as a backup to no source being present), to the best of my knowledge (and based on the its help page), the only way to do such is to disable the "Java Bytecode Decompiler" in the Plugins list.

Robers

Step 2 was the problem in my case. Thanks for your detailed answer. – Wandy

Surprisingly, openjdk sources are distributed as separate package in Ubuntu, i.e. openjdk-8-source. Step one really does help troubleshooting such things. – Nunciata

This helped to me. Especially step 1. Just in case someone cannot find the src.zip here is how it can be added on Ubuntu: sudo apt-get install openjdk-8-source. And the link to the ubuntu forum: askubuntu.com/questions/755853/how-to-install-jdk-sources – Telles

Answer 2

After ensuring my sources were attached, checking the source ZIP, invalidating the IntelliJ cache and restarting, I was still having the same problem.

To fix it, I created the project anew File > New > Project From Existing Sources..., and when I got to the library selection step I deselected the .jars for my own modules.

Listlessness