Java lovers: A magical phenomenon , what is the intention of playing it ? Or fate dictates - subclass inherits the methods of the parent class (ps: really does get confused )


  class Base
  {
      private String showMe()
      {
          return "Base";
      }
  
      public void print()
      {
          System.out.print(showMe());
      }
  }
  
  public class Sub extends Base
  {
      public String showMe()
      {
          return "Sub";
      }
  
      
  //    public void print()
  //    {
  //        System.out.print(showMe());
  //    }
      
      public static void main(String[] args)
      {
          Sub sub = new Sub();
          sub.print();
      }
  }

uncomment the comment section , try the outcome ?
------ Solution ---------------------------------------- ----

according to the test results should be just a reference
itself does not follow exactly the same way as the parent class
or inherited method does not show is this


  public void print()
      {
          super.print();
      }

but do not know if this is what I understand
specific java inheritance will have to see is how to achieve it ? wait downstairs Daniel answered
------ Solution ------------------------------ --------------


  public static void main(String[] args)
  {
      Sub sub = new Sub(); 
      sub.print(); 
      /*
       sub 自己没有print所以调用的是Base 的print，因为继承了Base。
       Base 的print 方法调用的showome() 是this.showme()，
       Base中的showme 是private 的，不能被重写，所以不会检查子类有没有重写直接调自身的showme()
       ------
       去sub的print注释后，调用shome 直接就是调用自己的print 压根就跟继承没多少关系
       因为你使用的是Sub sub = new Sub(); 非 Base sub = new Sub();
       -----
       试一下把Base 的showme() 改为public ，其它维持原状，相同的程序就会打印sub了。
       调用Base 的print --> print 调用this.showme() ，因为new 的是Sub,而且showme 是public是可被重写的
       就会检查Sub有没有重写showme ，发现重写了调用Sub的showme
       */
  }

------ Solution -------------------- ------------------------
looked at , the landlord always wanted to do not understand is the method override , recommended a good understanding about it.

subclass appear exactly the same with the parent class method , there will be an overwrite operation , also known as rewritten or replication.
subclass private method can not be overridden.
overridden method in a subclass , the continued use of overridden methods through super. function name obtained .
------ Solution ---------------------------------------- ----
individuals a guess: the inheritance of the parent in the child 's class at compile java into . java byte code at compile time when the method
will first determine the methods inside the variable modifiers if private ( example, here 's private String showMe () returns a string as can be seen as the variable bar ) directly in the parent class compiled
If the method is not inside the private variable modifier is placed subclass compiled
did not look at the bottom of the compilation process so please correct me guess the next
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seeking great God, and explain why the outcome will be ?

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shown in subclasses parent class inherited methods and do not show such a result the difference ?
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is not a rewrite of a rewrite do not
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which overrides which did not rewrite ?
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annotated output is not overridden base
uncomment rewritten output is sub

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Why would rewrite the first print () can be inherited , and secondly, I did not change from the parent class print () in any way !
Is it just show up on behalf of the rewrite yet ?
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1. uncommented , output : Base.
2. release notes, output : Sub.
showMe parent class method , private properties means can not be inherited . Therefore, the main function , the subclass method showMe quoted are subclasses own . But the print is the public, so subclasses can inherit the parent class .
So, no comment, subclass references print method of the parent class , parent class print method is called the Father of his showMe, namely printed base.
release notes after the subclass will print method calls itself showMe methods, namely printed sub. .
I have not tried , but the reasoning that, if really wrong , the landlord when I have not. . .
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layer Lord " so, no annotations . . ." here should be " annotated when " it should be wrong !
I create and debug it, your reasoning is correct, it is indeed run in this way , but still to explain :
Why I inherited method appears intact will impact on the results ?
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In fact, I was wrong, and my colleague is right , private it is not inherited , but can not be accessed by subclasses . . My question. .
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then what ? Why would a method inherited intact will show an impact on the results ?
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again, if private be inherited , but inherited not be used, then why should inherit ?
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first private can not be inherited

annotation
because subclass inherits the parent class print method
So sub.print ();
At this point in a subclass called like this


   public void print()
      {
          super.print();
      }

actually call the parent class print method
output is the base

After removing comments

subclasses override the parent class print method
sub.print (); calling a subclass own methods
output is base

In fact, this is similar to


  Class A {
    public static void main(String[] args) {
         A a = new A();
         System.out.println(a.toString()); 
    }
  }

This output is the address of a

When A after rewriting the toString method


  Class A {
    private String toString() {
     return "a";
    }
  
    public static void main(String[] args) {
         A a = new A();
         System.out.println(a.toString()); 
    }
  }

the output is a

rewriting is a subclass method name , return type, keep the parent class parent class unanimously agreed to keep the scope or extensive than the parent class

So the landlord when sub subclass uncomment clearly overrides the parent class method
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1, first of all there is no change in the parent class print ( ) method content, just show up , this is a rewrite ?
2, followed by the no will print () is displayed, which is commented out print () , a sub-class is definitely inherited the print () method , then what is this so-called inherited a reference to the parent class , or itself have real code to write a print () method in the interface just did not show it ?
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according to the test results should be just a reference
itself does not follow exactly the same way as the parent class
or inherited method does not show is this


  public void print()
      {
          super.print();
      }

but do not know if this is what I understand
specific java inheritance will have to see is how to achieve it ? Daniel waiting downstairs to answer constructor inheritance is !
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constructor , then
is new when the first call to a subclass of the parent class constructor and then call your own constructor do ?

seemingly not the same , right ?
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constructor , then
is new when the first call to a subclass of the parent class constructor and then call your own constructor do ?

seemingly not the same , right ? I said in another post inside the order, you can look at :
http://bbs.csdn.net/topics/390635323?page=1 # post-396093690
I mean, the default constructor , if not stated subclass out whether the call should also be a reference to the parent class !
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seemingly upstairs explain clearly points than I

learn
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I understand your idea, but there is another question is: Why is the print () in the subclass does not move completely written out , it becomes a sub-class custom method of rather than inherited from the parent class method ?
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to sub the print notes , call shome directly is to call your own print are they just do not have much relationship inheritance
because you are using a Sub sub = new Sub (); non- Base sub = new Sub ();

Sub sub = new Sub (); / / This is the parent class does not exist subclass relationship , declare that Sub, Sub is instantiated
sub.print (); / / First check that they have no print, if there is a direct call your own print. Before the print will call the parent class because he did not Sub print, so go see if there is print the parent class

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inheritance should only be a reference to the parent class method
I drew a map subclass relationship with the parent class should be like

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when you call sub.print () when subclass does not have this way it will go to the parent class
like to call the parent class upstairs showMe () when it is not inherited because showMem direct output base
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I know what you mean , however. . . My question is : Why is displayed print () becomes a subclass defines its own way , while not displayed or inherited method , just a " show " will be able to produce such a result ?
If print () is a sub- class of its own display method defined , then the subclass inherited from the parent class print () method which went ?
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that the print () displays whether the parent class method overrides ?
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that the print () displays whether the parent class method overrides ?

is a subclass override print () method after subclass will have a print ()
When calling sub.print () can be found when subclass print () method on the direct implementation of the
then call the subclass itself showMe () on the output sub a
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subclasses override print () can not be said to be displayed
because the method does not hide but this method is not a subclass
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that the print () displays whether the parent class method overrides ?

is a subclass override print () method after subclass will have a print ()
When calling sub.print () can be found when subclass print () method on the direct implementation of the
then call the subclass itself showMe () on the output of the sub That is to say , after no longer override the parent class print () method with references ?
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had cut off after a reference to the parent class , the so-called burning bridges ?
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that the print () displays whether the parent class method overrides ?

is a subclass override print () method after subclass will have a print ()
When calling sub.print () can be found when subclass print () method on the direct implementation of the
then call the subclass itself showMe () on the output of the sub        That is to say , after no longer override the parent class print () method with references ?

rewrite adopted after sub.print () is not visit parent class method
only through super.print () to access

------ For reference only ---------------------------------- -----
that the print () displays whether the parent class method overrides ?

is a subclass override print () method after subclass will have a print ()
When calling sub.print () can be found when subclass print () method on the direct implementation of the
then call the subclass itself showMe () on the output of the sub            That is to say , after no longer override the parent class print () method with references ?

rewrite adopted after sub.print () is not visit parent class method
only through super.print () to access
you change the code :
Sub sub = new Sub ();
read:
Base sub = new Sub ();
will find the same result !
------ For reference only -------------------------------------- -
had cut off after a reference to the parent class , the so-called burning bridges ?

This can not be called " quote " I do not know
I did not feel before rewriting print () is part of the parent class
subclass inherits the parent class is because the relationship between the call sub.print () is not found in the subclass print () to go to the parent class
after she had rewritten print () do not need to go looking for the parent class

------ For reference only ---------------------------------- -----
had cut off after a reference to the parent class , the so-called burning bridges ?

This can not be called " quote " I do not know
I did not feel before rewriting print () is part of the parent class
subclass inherits the parent class is because the relationship between the call sub.print () is not found in the subclass print () to go to the parent class
after she had rewritten print () do not need to go looking for the parent class
There are no other thoughts can only agree with this knowledge !
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had cut off after a reference to the parent class , the so-called burning bridges ?

This can not be called " quote " I do not know
I did not feel before rewriting print () is part of the parent class
subclass inherits the parent class is because the relationship between the call sub.print () is not found in the subclass print () to go to the parent class
after she had rewritten print () do not need to go looking for the parent class
       There are no other thoughts can only agree with this knowledge !

so you have other large cattle to doubts ah in the end is not the case

for the hair did Daniel do ?
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had cut off after a reference to the parent class , the so-called burning bridges ?

This can not be called " quote " I do not know
I did not feel before rewriting print () is part of the parent class
subclass inherits the parent class is because the relationship between the call sub.print () is not found in the subclass print () to go to the parent class
after she had rewritten print () do not need to go looking for the parent class
           There are no other thoughts can only agree with this knowledge !

so you have other large cattle to doubts ah in the end is not the case

for the hair did Daniel do ? I have discussed this problem before , because the layers of references cause java performance is low. But thank you very much , I'm sure you will as a good woman to become a Piece of men !

------ For reference only ---------------------------------------
been cut off after the parent references to a class , the so-called burning bridges ?

This can not be called " quote " I do not know
I did not feel before rewriting print () is part of the parent class
subclass inherits the parent class is because the relationship between the call sub.print () is not found in the subclass print () to go to the parent class
after she had rewritten print () do not need to go looking for the parent class
               There are no other thoughts can only agree with this knowledge !

so you have other large cattle to doubts ah in the end is not the case

for the hair did Daniel do ?        I have discussed this problem before , because the layers of references cause java performance is low. But thank you very much , I'm sure you will as a good woman to become a Piece of men !