Eclipse Open declaration in Java project

Question

In an Eclipse SVN project I have a problem; when I tried to open a declaration of one class, I got this error:

Problems opening an editor Reason : projectna         


        

Answer 1

I am using Eclipse Oxygen.2 (4.7.2). I don't see Project Facets after clicking project -> Properties. My solution is right click the project and click Configure, then select configure and detect nested projects, Eclipse will automatically generate the nested projects for you. May get some build errors in the new created projects, that should be easy to fix.

Answer 2

I had the same in Eclipse Luna on Debian 8. I was missing the .classpath file when checking out from SVN. I manually copied it and changed some path names, refreshed the project and it was working again.

Answer 3

Right Click on the project -> Properties -> Project Facets -> Click on the Configuration Link -> Click on Apply Button -> Click on OK button.

The above steps should set your project as a Java project.

Answer 4

There is a bug in Eclipse (in Luna at least) for a very specific workflow, which might not be the answer to this specific question, but might be helpful for others.

If you perform an import into the src (meaning src folder has focus before performing import) folder from an extracted jar (as source code), and you place breakpoints in the nested *.java files in the nested packages, it won't hit those breakpoints. In order to get things to work, you must keep hitting F3 instead of using "Open Declaration" to get to the *.java file you want to set a breakpoint in, then add the breakpoint by double clicking in the far left margin. Then Run > Debug As > Java Application.

Answer 5

I had this problem, too. It looks like after a search-in-workspace Eclipse opened a wrong file.

I pressed Ctrl + Shift + H (Open Type in Hierarchy), typed in the class name, and opened it. The file opened in a new tab, and everything was navigable again.

The difference in icons is:

Answer 6

It might lack a builder. Check your PROJ_HOME/.project that should be like:

<?xml version="1.0" encoding="UTF-8"?>
<projectDescription>
    <name>the-one-user</name>
    <comment></comment>
    <projects>
    </projects>
    <buildSpec>
        <buildCommand>
            <name>org.eclipse.jdt.core.javabuilder</name>
            <arguments>
            </arguments>
        </buildCommand>
    </buildSpec>
    <natures>
        <nature>org.eclipse.jdt.core.javanature</nature>
    </natures>
</projectDescription>

Ref: FAQ How do I add a builder to a given project?