java - Protected access modifier use on Class's Constructor -

i clear using private, default , public access modifiers on public class's constructor.

if constructor private, class object can created in class only.

if constructor default, class object can created in package's classes only.

if constructor public, class object can created in class.

i not clear protected constructor. example:

default constructor

package com.test; public class practiceparent {     practiceparent(){       //constructor default access modifier         system.out.println("practiceparent default constructor");     } }  package com.moretest; import com.test.practiceparent; public class test extends practiceparent {  //error. implicit super constructor practiceparent() not visible default constructor. must define explicit constructor     public static void main(string[] args) {         practiceparent pp=new practiceparent();     //error. constructor practiceparent() not visible     } } 

i understand these errors. since parentpractice class in other package , constructor default, not visible test class default constructor call super() implicitly. also, object can't created due non visibility of constructor.

protected constructor

but class test extending parentpractice , parentpractice having protected constructor, there no first error i.e. error in calling super() implicitly test's default constructor. implicit super constructor practiceparent() visible test's default constructor practiceparent object can not created. error shown constructor practiceparent() not visible.

package com.test; public class practiceparent {     protected practiceparent(){     //constructor protected access modifier         system.out.println("practiceparent default constructor");     } }  package com.moretest; import com.test.practiceparent; public class test extends practiceparent {  //no error     public static void main(string[] args) {         practiceparent pp=new practiceparent();     //error. constructor practiceparent() not visible             /*test t=new test();     outputs "practiceparent default constructor"*/     } } 

why super() called not possible create new practiceparent object?

public class test extends practiceparent {  //no error         public static void main(string[] args) {             practiceparent pp=new practiceparent();     //error. constructor practiceparent() not visible             test t=new test();     //outputs "practiceparent default constructor"         }     } 

what here have test extend practiceparent, meaning test itself can use protected constructor, because inherits it.

practiceparent pp=new practiceparent();     //error. constructor  

this regular instantiation , still uses, or, tries use public constructor, doesn't exist. produce same effect/result if had called anywhere else in application.