java - 包私有(private)类中的公共(public)方法

Question

在包私有(private)类中将方法标记为 public 有区别吗？

class SomePackagePrivateClass
{
    void foo();          // package private method

    public void bar();   // public method
}

foo 和 bar 这里的可见性有什么实际区别吗？

Answer 1

使用继承的示例:

A.java

package pkg1

class A {
  void foo();
  public void bar() {};
}

B.java

package pkg1

public class B extends A{

}

C.java

package pkg2

public class C {
  public void doSomething() {
   B b = new B();
   b.bar(); //ok
   b.foo(); //won't work, since foo() is not visible outside of package 'pkg1'

   A a = new A(); //won't work since A is not visible outside of package 'pkg1'
   a.bar(); //won't work, since a cannot be created
  }
}