References of Array and Objects in Java-CodePudding

In java array carries reference to a memory location and objects does that too. So when we create an array of objects, does that mean that the array carries reference to more references?

I asked this question to my professor, but didn't quite understand what he explained.

CodePudding user response：

When you write:

  Object[] array = new Object[10];

the variable array contains a reference. This reference points to an array object, which can contain 10 references. These references are all null at the point that the array is created.

Once you write:

  array[0] = new Object();

array[0] now contains a reference to an Object instance.

CodePudding user response：

Yes.

Suppose you have code like this:

 class Foo { ... 
     public int getBar () { ... 
     public void setBar (int bat) { ...

Now, elsewhere you have code like this:

 Foo [] glorblarr = new Foo [12]; 
 Foo flarg = new Foo ();
 ...  
 flarg.setBar (100);
 glorblarr [7] = flarg;
 System.out.println (flarg.getBar ()   "  "   glorblarr [7].getBar ());
 glorblar [7].setBar (987);
 System.out.println (flarg.getBar ()   "  "   glorBlarr [7].getBar ());

You should expect the output to be this:

  100  100
  987  987

At this point, globarr [7] refers to the same Object as flarg. That is, one Object, but it is accessible via two names / references. At least until one of the references is changed to point to something else (or null), one is an alias for the other.