Created attachment 154234 [details]
Illustration of error flags.

Just recently however, came across a problem with some of my classes showing many error flags on previously error free code:
Attempts to compile would fail with may warnings ‘cannot find symbol fireButtonEvent(int, String)…

 

I quickly realised that the problem had arisen because I had included source stub files (declarations and method signatures without proprietary implementation code) in the Nebeans library along with the usual class file .jar and Javadoc references.

What is curious is that if I remove the source stub files from the library, the error flags remain but the code will compile. 
If I close the IDE after removing the source stub files from the library definition, clear the cache and restart, the error flags disappear.

On further investigation I found that all the error flags were due to a single source stub file..

In the screen-shot above, all the nnnWizardPages are all extended from a superclass AbstractWizardPage. When I look at AbstractWizardPage (with the src-stubs installed),  I see the following, unremarkable  code:

[code]
package com.jidesoft.wizard;

public abstract class AbstractWizardPage extends AbstractDialogPage {

     public static final int LEFTPANE_NONE = 0;

… remainder of class definition
[/code]

Now the fireButtonEvent(int, String) method is declared in the class AbstractDialogPage and the Netbeans error is ‘cannot find symbol fireButtonEvent(int, String)…’ .
In the code above, there is NO import for the class AbstractDialogPage. 

If I navigate to the source code for AbstractDialogPage  having first removed the offending src-stub files, I see the following code:

[code]
package com.jidesoft.wizard;

import com.jidesoft.dialog.AbstractDialogPage;
import com.jidesoft.dialog.PageListener;
import java.awt.Image;
import java.util.List;
import javax.swing.Icon;
import javax.swing.JComponent;
import javax.swing.border.Border;

public abstract class AbstractWizardPage extends AbstractDialogPage {

    public static final int LEFTPANE_NONE = 0;
… remainder of class definition
[/code]
    
So, now I have a much more complete view of the source code from the Netbeans decompiler and importantly, there is an import for AbstractDialogPage and I have no errors.

I raised the issue with Jidesoft.. Their response was: “ If an IDE depends on the import statements in the source code to implement the error highlighting, something is wrong about the IDE. I didn't check eclipse but IDEA has no problem with the stub source without imports.”

Now I’m not really qualified to judge the situation but my observation and question is simple:

It seems that when available, Netbeans uses the source code in preference to the compiled .class to implement error highlighting in this case.