I have a Java class file that I'm modifying inside a large project.

Inside that Java class, I have a main() function, which I use to test some functionality of the class's methods.

I modify contents of this file, and then I hit "Shift + F6" to run the file.

The file executes, however, I've noticed that somehow it's one compilation behind.  

More precisely, what I mean by this is that let's say that I have the line:

  System.err.println("Hello world 1");

in my class file.

I clean the project and rebuild and run: I get "Hello World 1".

Now, I'm going to change the line to :

  System.err.println("Hello World 2");

I don't clean nor rebuild the project.  Instead, I hit "Shift + F6".  The file executes, but I get: "Hello World 1".

I now change the line to:

  System.err.println("Hello World 3");

I don't clean nor rebuild.  Instead, I hit "Shift + F6".  The file executes, but I get: "Hello World 2".


NOTES:

In the properties section, I have "Compile on Save" enabled.

I don't believe that I've seen this when I hit "F6" to run the entire project, but I've definitely seen it on "Shift +
F6" on occasion.