Why is the constructor of TestServices class being called multiple times in my VSP project

[amilamiandara]

I created a vsp project, I need to call java methods in the odesign file to deal with some complex logic, I write the methods in the TestServices class, but I find that every time I do an operation on the diagram, the constructor of the TestServices class will be called many times, which is very different from the result of guessing once executed. I don't understand why the constructor of the TestServices class is called so many times?