Some notable problems in Java

1, a source file can only have one class is public, the other is the default permissions;

2, a class can only be public or the default permissions (that is, no modifier meaning);

3, the source file of the public class name must be consistent with the file name, or compile error;

4. The package must be the first line of Java source files, and if not, the default packages will be placed under a default packet;

5, import must be in the package after the other code, no one fails to load, the compilation does not pass;

6, if the constructor is modified by private, then even if the class is a public class, can not create objects, the ability to create objects is only one, is the static method of the class to create objects;

Some notable problems in Java