A Java source file that can have more than one class, but only a public-decorated class

Each Java source file is a writing unit for a Java compiler. Each time the compiler writes a. java file (a compilation unit), it outputs many of the From class files that correspond to the names of the Java file classes, not just the public adornments. However, the public class is the open interface that is used to compile the unit existence. If not, the run will error, indicating that the loaded class could not be found.

Public is the equivalent of a main class. But there can only be one main class, and the name is the same as the Java source file name, as the only interface.

A Java source file that can have more than one class, but only a public-decorated class