Groups > comp.lang.java.programmer > #32620

Re: can you give me some hints on the Oracle Java SE related certificates?

Newsgroups	comp.lang.java.programmer
Date	2015-09-21 13:57 -0700
References	(3 earlier) <mthit8$784$1@dont-email.me> <4245d965-6d79-4bdf-accd-dc51520d3273@googlegroups.com> <mti4pt$igj$1@dont-email.me> <313f817e-9d7c-4939-a971-7e2b2a85d35f@googlegroups.com> <mtjppt$g5v$1@dont-email.me>
Message-ID	<430f5ded-3382-476a-ae5e-ef12427e1542@googlegroups.com> (permalink)
Subject	Re: can you give me some hints on the Oracle Java SE related certificates?
From	John <xsli2@yahoo.com>

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On Saturday, September 19, 2015 at 10:02:34 AM UTC-4, Jeff Higgins wrote:
> On 09/18/2015 11:23 PM, John wrote:
> > On Friday, September 18, 2015 at 6:58:12 PM UTC-4, Jeff Higgins wrote:
> >> On 09/18/2015 02:11 PM, e.d.programmer@gmail.com wrote:
> >>> On Friday, September 18, 2015 at 1:52:38 PM UTC-4, Jeff Higgins wrote:
> >>>> How will Oracle Java SE certificates make your students more valuable.
> >>>> How much more valuable? More valuable to whom? Who says?
> >>>>
> >>>> ----
> >>>
> >>> Assuming they're not going to be self employed, the value is to a potential employer, which is hard to quantify because potential employers are not required to send rejection letters.  If you have a certification you're going to be far below someone with a US 4 year college degree in the programming field, unless you have a comparable degree, then that certification tagline could bump you ahead of them.
> >>> Just read the description of the certification and be sure it applies to the job you want or it may just be a waste of money.
> >>>
> >>
> >> I'm concerned that the topic of Java Certification didn't come
> >> up during an interview for the position of "Java instructor of
> >> computer science in a local college in a developing country in Asia"
> >>
> >> As a student trying to decide whether to enroll in a course led
> >> by the OP I would have been grateful for a pointer to this thread.
> >
> > Jeff:
> > If you really have nothing better to do, here is one Java SE question for you:
> > Can you explain to me why Java cannot have multiple inheritance? Please note, I am asking WHY. This is Java 101 question. I am sure you look shining when my future students look at your answer on this thread, or the opposite way. One of the other.
> >
> For some of your more curious students you might point to
> the chapter titled "Data Abstraction and Object Orientation"
> in:
> 
> Scott, Michael L. Programming Language Pragmatics.
> San Francisco: Morgan Kaufmann, 2000.
> 
> You may see all editions here:
> <http://www.cs.rochester.edu/~scott/pragmatics/>

Wow, Jeff:
I am asking(testing) you a question("Why Java cannot have multiple inheritance?") and you threw back to me a web link first and a book later. You are really "shining"!!!

Here is my answer to the question:

Suppose Java can have multiple inheritance, let's say both BaseA and BaseB are two concrete classes:

public class BaseA {
    public void sayHi(){System.out.println("Hi from A!");
}

public class BaseB {
    public void sayHi(){System.out.println("Hi from B!");
}

public class MyClass extends BaseA, BaseB { //multiple inheritance is not allowed
    public static void main(String[] args) {
       MyClass c = new MyClass();
       c.sayHi();  //Will it say "Hi from A!" or "Hi from B!"?
    }
}

For Java, in order to achieve multiple inheritance effect, we use interface:

public interface BaseC {
    public void sayHi();
}

public class MyClass extends BaseA implements BaseC {

    public void sayHi() {//MyClass must implement this method to be concrete
       System.out.println("Hi I am here!");
    }
    
    public static void main(String[] args) {
       MyClass c = new MyClass();
       c.sayHi();  //prints "Hi I am here"
    }
}

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