Whether there can be more than one external class in a. java file

Some time ago, a colleague asked me this question: can I have more than one external class in a. java file?

Answer: There can be more than one external class, but only a class that is modified by the public.

And if there is a class in the. java file that has a public type, the class name needs to match the. Java filename.

Example:

The following external classes are available in the file A.java

public class A1 will error, the error message is as follows: Prompts the public type of A1 must be defined in its own file

Therefore, a Java file cannot have a class of two public types at the same time.

Whether there can be more than one external class in a. java file