Source not found for internal java classes in eclipse

Question

I use eclipse and lots of times I need to open a source file of an internal class in java. I do this by pressing ctrl + click on that object. For example I want to see the codes of the Scanner class, and when I try to open it by ctrl + click on a Scanner object, it shows that, "source is not found". The error is this:

The JAR file in /usr/lib/jvm/java-8-openjdk-amd64/jre/lib/rt.jar has no source attachment.

You can attach the source by clicking Attach Source below:

And there is an Attach Source button under it. I searched a lot but all people had the same problem with the projects on their filesystem, not the internal classes. What should I do? Is there a way to change that /usr/lib/jvm/java-8-openjdk-amd64/jre/lib/rt.jar file?

Use a JDK rather than just the JRE. The JDK contains source and Eclipse will find it. — greg-449, Dec 31 '19 at 11:30
@greg-449 I don't know how to change it. I've installed `openjdk-8-jre` package. What should I install? — Mohammad Kholghi, Dec 31 '19 at 11:34
@greg-449 I had to install `openjdk-8-source`. Thanks anyway. — Mohammad Kholghi, Dec 31 '19 at 11:56

score 0 · Accepted Answer · answered Dec 31 '19 at 11:55

Just do

$ sudo apt install openjdk-8-source
$ sudo updatedb
$ mlocate src.zip

Copy the last command's location. It usually is /usr/lib/jvm/openjdk-8/src.zip.

Then, click Attach Source, and click on external locatoin. Then paste that command's output in the text field. (You can open the file by clicking on external file and finding that src.zip file in your filesystem.)

Source not found for internal java classes in eclipse

1 Answers1