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delete objects;

6 replies on 1 page. Most recent reply: Nov 9, 2011 4:05 AM by Vincent O'Sullivan

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Dimitris Paras

Posts: 12
Nickname: dimpars
Registered: Feb, 2005

delete objects; Posted: Feb 24, 2005 5:00 AM
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I am a c++ developer and i used to delete ojects with

object *obj=new object;
delete obj;

What shall i do in java, to delete an object from a linkedlist? for example

customer cc=(customer)(customers.getFirst());

Is it enough to remove it like this:

Customers.removeFirst();

Thank you in advance for your consideration!


Amol Brid

Posts: 43
Nickname: amolbrid
Registered: Feb, 2004

Re: delete objects; Posted: Feb 24, 2005 6:22 AM
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Hi,

Don't worry about deleting an object in Java. Garbage Collector (GC) will take care of it and object will be deleted.
Search for articles on GC on google to more about how GC works or best way is to read chapter 9 of "Inside JVM". Here is the online version http://www.artima.com/insidejvm/ed2/index.html

In C++ we have to explicitly delete object because their is not GC.

Regards,
Amol Brid.

Dimitris Paras

Posts: 12
Nickname: dimpars
Registered: Feb, 2005

Re: delete objects; Posted: Feb 24, 2005 10:47 AM
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ok thanks a lot!!!

perry anderson

Posts: 10
Nickname: anderson
Registered: Feb, 2005

Re: delete objects; Posted: Feb 28, 2005 4:09 PM
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actually, that's not exactly the full story

there is an implied way to remove the object from memory which comes in handy if your allocating alot of objects and need that space freed up as soon as possible


myObject = new MyClass();
myVector.add(myObject);

...
myVector.remove(myObject);
myObject = null;


the myObject = null drops a hint to the garabage collector that it's ok to free that objects space right away... which it usually does otherwise what happens is that unreferenced objects get collected till memory is needed and then a full gc process kicks in, pausing all operations until it's done. by helping out the gc with this simple operation, you are actually helping yourself by removing the need for a full garabage collection at a later time.

it works beautifully and came in really handy when i was developing an audio/video conferencing app in java and did not need the gc going bizzerk every five minutes....

- perry

perry anderson

Posts: 10
Nickname: anderson
Registered: Feb, 2005

Re: delete objects; Posted: Feb 28, 2005 6:25 PM
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public class MyClass() {
 
   public void static main(String[] args) {
 
     myObject = new MyClass();
     myVector.add(myObject);
 
     ...
 
     myVector.remove(myObject);
     myObject = null;
 
  }
 
}
 


hmmmm, that's nice

- perry

Ronan Masangcay

Posts: 1
Nickname: ronmass
Registered: Nov, 2011

Re: delete objects; Posted: Nov 6, 2011 10:19 PM
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Hi! Sorry am quite new to JAVA. Please explain where did myVector come from?

Thanks,

Ronan

Vincent O'Sullivan

Posts: 724
Nickname: vincent
Registered: Nov, 2002

Re: delete objects; Posted: Nov 9, 2011 4:05 AM
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It didn't come from anywhere. The code example is just an simple example that would fail to compile.

myVector should have been declared before it was used, either in the method:
Vector myVector = new Vector();
or outside the method but inside the class:
private Vector myVector = new Vector();
(For what it's worth, the Vector class is considered obsolete and not used.)

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