When I write a class Widget.java
public class Widget {
int data;
String name;
}
will the compiler-generated constructor be public or default?
public would be like
public class Widget {
int data;
String name;
public Widget() {}
}
whereas default similar to
public class Widget {
int data;
String name;
Widget() {}
}
It depends on your class visibility.The compiler uses the class visibility and generates a no-arg default constructor with the same visibility
As said in JLS
If a class contains no constructor declarations, then a default constructor that takes no parameters is automatically provided:
- If the class is declared public, then the default constructor is implicitly given the access modifier public;
- If the class is declared protected, then the default constructor is implicitly given the access modifier protected;
- If the class is declared private, then the default constructor is implicitly given the access modifier private;
- Otherwise, the default constructor has the default access implied by no access modifier
As classes visibility is public, it will always be a public constructor.
It will be public
as the class visibility is public
public Widget() {}
It will be public Widget() {}
Depends on class visibility. For your class dafault constructor is going to be public.
In a class type, if the class is declared public, then the default constructor is implicitly given the access modifier public (§6.6); if the class is declared protected, then the default constructor is implicitly given the access modifier protected (§6.6); if the class is declared private, then the default constructor is implicitly given the access modifier private (§6.6); otherwise, the default constructor has the default access implied by no access modifier.
From here.
If your class is public then the default constructor would be public so in your case, Since the Widget class is public its default constructor supplied by the compiler would also be public. See this
来源:https://stackoverflow.com/questions/21750609/will-the-compiler-generated-default-constructor-be-public