Java：无法访问扩展子类中超类的受保护成员

作为声明类的子类的其他包中的类只能访问其自己的继承

protected

package FirstChapter;import JustRandomPackage.*;public class ATypeNameProgram extends YetAnotherClass{    public ATypeNameProgram() {        System.out.println(this.variable); // this.variable is visible    }}

…但不是其他对象的继承

protected

package FirstChapter;import JustRandomPackage.*;public class ATypeNameProgram extends YetAnotherClass{    public ATypeNameProgram() {        System.out.println(this.variable); // this.variable is visible    }    public boolean equals(ATypeNameProgram other) {        return this.variable == other.variable; // error: YetAnotherClass.variable is not visible    }}