If you already know why the following code fail to compile, then you don’t need to continue reading! // File: MyClass.java public class MyClass { // field, constructor, and // method declarations } public class MyClass2 { // field, constructor, and // method declarations } However, if you are surprised then continue reading: Above code fails to compile because there are two public classes declared in a single file. If you need to define multiple classes in a single file you need to declare only one Public top level class.