The Java Language Specification, Third Edition

6.6.3 An Example of Access Control NAMES
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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 by a
qualified superclass constructor invocation of the form E.super(. ..), where
E is a Primary expression, then the access is permitted.
• If the access is by an anonymous class instance creation expression of the
form new C(. ..){...} or by a qualified class instance creation expression of
the form E.new C(. ..){...}, where E is a Primary expression, then the
access is permitted.
• Otherwise, if the access is by a simple class instance creation expression of
the form new C(...) or by a qualified class instance creation expression of the
form E.new C(. ..), where E is a Primary expression, 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) only from within
the package in which it is defined.
6.6.3 An Example of Access Control
For examples of access control, consider the two compilation units:
package points;
class PointVec { Point[] vec; }
and:
package points;
public class Point {
protected int x, y;
public void move(int dx, int dy) { x += dx; y += dy; }
public int getX() { return x; }
public int getY() { return y; }
}
which declare two class types in the package points:
• The class type PointVec is not public and not part of the public interface
of the package points, but rather can be used only by other classes in the
package.
• The class type Point is declared public and is available to other packages. It
is part of the public interface of the package points.
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