Program does not react to changes after editing Java Build Path

[Tartaglia]

Dear all,

for some reason my program does not react to changes anymore when I edit the Build Path. To be specific, after creating my class and entering my code, I add a project and from then on, none of the changes to the source code are implemented and instead the Eclipse runs the last version that was saved before editing the build path. I have tried this with the Hello World program instead of my actual code and still got the same problem:

package demo;

public class Model {

	public static void main(String[] args) {
	     System.out.println("Hello World!");
		    }
	
}

So for instance if after including the project in the build path I would change something in the code ("Good Morning World" instead of "Hello World"), Eclipse would still run the previous version (so I would still get "Hello World" as the output). Then if I erase the project from the build path, everything works fin again, that is, my changes are incorporated again. Does anyone have an idea, what the cause might be?

Thank you for your help and best regards,
Tartaglia

[RichersooN]

You should use the drop down list beside the run button in eclipse

[Tartaglia]

Thank you RichersooN for your quick reply. What exactly would you suggest for me to choose from the drop down list?