I have a problem when executing my program, I get a little hammer where the classes are and it won't let me execute it. I get that hammer:
The strange thing is that all the classes are there and the frames but it does not let them execute, can someone help me?
You have to right click on the project, and click on Property, sometimes the "hammer" that appears is because you have a problem with a library or .jar file
When you open your project's Properties window, check the Sources and Libraries options. The problem may be in one of these two. Sometimes it's just adding the library or .jar file correctly or simply removing an incorrect path.