Eclipse - Source not found

Question 1

Well it turns out the solution was anticlimactic. When Balder's recommendations did not work I tried debugging one of the stock OpenFire plugins and it worked just fine. I then created a new plugin from scratch, and by doing nothing other than adding the source to the project (Right-click on the project -> New -> Source Folder) it also worked just fine. I have no idea why Eclipse refuses to see the source for my original plugin, but I moved all my code and libraries over to the new plugin and debugging is working as expected.

Question 2

Personally, I have no good experience in Eclipse JDT, when adding a source folder at the time it hits a break point. What I always prefer to do, is adding the source folder before debugging:

Select Project/Properties/Libraries
Select your library and "edit..." the source attachment
Select either the corresponding source folder or the zip/jar containing the package

After that, you should be able to open the source files in the virtual "Referenced Libraries" folder (directly below the "JRE System Library" folder inside the project), or when opening a reference to a linked class file from within the JDT editor. If you are able to access the source, then you should also be able to at least stop at the break point and see the corresponding source.

Else, you will have to check again, if the source folder is really valid: The source folder or source archive must contain the folder with the name of the root package of the library (e.g. the default Java "src.zip" inside the JDK folder also includes a corresponding "java" folder at its root). When in doubt, extract the archive and select the parent folder of the package you are interested in - sometimes source archives might be a mess or incompatible to JDT.

If this has been assured and it still doesn't work, chances are, that your linked source folder does not correspond to the compiled version of the library. Usually JDT will handle such inconsistencies fine, but if you try to open a source file, that is entirely different than the corresponding class file, you will encounter problems. In this case I would suggest either downloading the correct source version of the library, or recompiling the library from the source, if all else fails.

If opening a referenced source file from withing the JDT editor does work fine, and you are still unable to open the source files when a break point is entered during debugging, then most likely the class files are missing the line numbers of the corresponding source file. Again, you will have to recompile the library from the source in this case.

Finally, it is also possible to overwrite the default source lookup by specifying source folders or archives in the source tab of the launch configuration. But you should normally not need to do this, when your build path is configured correctly. From the Eclipse Help:

The Source tab defines the location of source files used to display source when debugging a Java application. By default, these settings are derived from the associated project's build path. You may override these settings here.

Question 3

I had this very annoying problem for a long time but was finally able to solve it. In my case, a null pointer exception was being thrown somewhere in Java's Transformer.IsRuntimeCode(ProtectionDomain) function.

I didn't really need to know about this since the exception was being caught and handled, but eclipse would pause debugging every time this happened and tell me that the source wasn't available. As a result, I constantly had to keep pressing the button to continue code execution.

In order to prevent this from happening, I:

 1. Clicked on the "Breakpoints" window at the bottom of the debugging
    screen
 2. Right clicked "NullPointerException"
 3. Unchecked "Caught"

This prevented the debugger from pausing program flow during a caught NullPointerException.alt text

_{(source: SharpDetail.com)}

And this another one as:

Eclipse doesn't crash. You're trying to step into a method, where eclipse doesn't know where to find the source (*.java) files and informs you about this. Here is how to tell eclipse where to look. Go to

Window->Preferences->Java->Installed JREs,select the JRE you are using and click Edit.

There, select all of the jar files in the list you see and and click Source Attachment....

In the window that shows up, select the fille src.zip, which is in your JDK folder (if you didn't uncheck it while installing the JDK). On the machine I'm on right now, that is

C:\Program Files\Java\jdk1.7.0_07\src.zip.

Save all your changes (possibly restart eclipse) and you won't see that error again.

Question 4

Many times you put jar files in eclipse IDE as referenced libraries when binary version of application was downloaded. Usually done so by configuring the build path. But the binary does not have the source files. You have Binary version and source version of application.

One simple way is to download the source libraries that you also use maven to build the project. Keep somehwere, may be inside your project workspace.

Now while seeing the class file (from eclipse, jar exploded) you may see the source not found, fine.... there is a button below and click on that, a new window opens and there select add external folder.

Reference it to the src folder of the source you downloaded(not the binary one) and kept somewhere as said above and it will show the class details from that.

Question 5

I fixed this issue with doing the following:

Click at the menu Window - Preferences - Debug - Step Filtering And check all the packages like the following image.

(Step Filtering)

Then, debug again your project and thats it.

Best regards,

Question 6

In my case, I had a breakpoint in the class declaration. I mean in the next line.

public class GenerateInterface implements JavaCall {

So, the debugger stopped in that line and showed the following message:

Source not found

I think unconsciously activate the breakpoint in that line.