Introduction to Programming

Building the application

Behind the scenes, the IDE compiles the code you are writing every time you change it. For example, try to remove the first letter, M, in the name of the class in the right pane. IDE will immediately warn you about the syntax error:

If you navigate your mouse to the red bubble, or any red line that underscores the class declaration in the preceding screenshot, you will see the Class 'yApplication' is public, should be declared in a file named 'yApplication.java' message. You may recall that we talked about it in Chapter 2, Java Language Basics.

Each .java file contains only one public class. The file name must match ...