Why can't I use protected constructors outside the package?

Question

Why can't I use protected constructors outside the package for this piece of code:

package code;
public class Example{
    protected Example(){}
    ...
}

Check.java

package test;
public class Check extends Example {
  void m1() {
     Example ex=new Example(); //compilation error
  }
}

1. Why do i get the error even though i have extended the class? Please explain

EDIT:

Compilation error:

The constructor Example() is not visible

Answer 1

Usually protected means only accessible to subclasses or classes in the same package. However here are the rules for constructors from the JLS:

6.6.2.2. Qualified Access to a protected Constructor

Let C be the class in which a protected constructor is declared and let S be the innermost class in whose declaration the use of the protected constructor occurs. Then:

If the access is by a superclass constructor invocation super(...), or a qualified superclass constructor invocation E.super(...), where E is a Primary expression, then the access is permitted.

If the access is by an anonymous class instance creation expression new C(...){...}, or a qualified anonymous class instance creation expression E.new C(...){...}, where E is a Primary expression, then the access is permitted.

If the access is by a simple class instance creation expression new C(...), or a qualified class instance creation expression E.new C(...), where E is a Primary expression, or a method reference expression C :: new, where C is a ClassType, then the access is not permitted. A protected constructor can be accessed by a class instance creation expression (that does not declare an anonymous class) or a method reference expression only from within the package in which it is defined.

As an example, this does not compile

public class Example extends Exception {

    void method() {
        Exception e = new Exception("Hello", null, false, false);
    }
}

but this does

public class Example extends Exception {

    Example() {
        super("Hello", null, false, false);
    }
}

and so does this

public class Example {

    void method() {
        Exception e = new Exception("Hello", null, false, false) {};
    }
}

So the rules are clear, but I can't say I understand the reasons behind them!