Explicitly tagging an object as unused

Just read an article on gc tuning (http://www-106.ibm.com/developerworks/java/library/j-perf06304/?ca=dgr-lnxw07BlogFix)
where memory leaks are caused by the so called "unintentionally retained objects".
Currently, detecting memory leak in Java is done using memory profiler to monitor
memory usage and select which objects are suspected to cause of memory leaks.
Then, the programmer must decide/guess which of the suspected objects really cause
memory leaks.
Is it worthed to provide an API that explicitly tags an object as unused, so that memory
profilers can find which objects are 100% the cause of memory leak? The notion of this
API is similar to free in C, however, this API does not affect the decision made by gc
regarding the reclaimability of an object, nor does it force gc to reclaimed the object.
Object marked by this API means "I'm no longer needed by the user/program/algorithm.
Hence, I should be able to be reclaimed by gc. If gc deemed I'm still referenced, this
means the programmers make mistakes, and thus, they must fix the program".

Just read an article on gc tuning where memory leaks are caused by the so called "unintentionally retained objects".Quote: From the final memory profile (Figure 3), with the major memory leak eliminated, we can see that there still is another "low grade" leak, but this leak is small enough that it can be ignored until the next release.
If you are getting memory management advice from articles by people who are happy to release software that they know is leaky, then you're in trouble. (OK, so my background is flight control software where leaks would be a matter of life and death, but these people seem to have no sense of personal honour.)
Currently, detecting memory leak in Java is done using memory profiler to monitor memory usage and select which objects are suspected to cause of memory leaks.Only do what is necessary to perform the required functionality. If having a reference to an object is functionally necessary, then that reference is required and will not be a leak. If you have a reference that is not required for the functionality, then you shouldn't have that reference any more. Cases where performance requires that a value be cached in case it is may be needed are already catered for with the WeakReference and SoftReference APIs.
Is it worthed to provide an API that explicitly tags an object as unused, so that memory profilers can find which objects are 100% the cause of memory leak? No, for the same reason that there is no goto in Java. If you are writing software that is so convoluted you don't know what objects are referencing each other, adding an API that encourages you do that more will not help you.
If gc deemed I'm still referenced, this means the programmers make mistakes, and thus, they must fix the program".If you are debugging badly written code, and do not have access to a static analysis tool which will tell you where your objects are being referenced, then you have the option of creating a reference queue and a phantom reference to your suposedly unreferenced object, clearing all references in your algorithm, forcing gc, and then asserting that the phantom reference was cleared.
Pete

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applet tag vs Object tag

As per W3Schools HTML applet tag is not supported in HTML5. Need to use <Object> tag instead of <applet> tag.
For more details follow this link: http://www.w3schools.com/tags/tag_applet.asp
http://dev.w3.org/html5/spec/obsolete.html#the-applet-element
Point 11.2 Non-conforming features
So, I go ahead and the change the code as below depicted.
Below code that is working with <APPLET> tag:
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style    = "position:absolute;border:0px;left:184;top:95;height:180;width:364;"
code     = "jtreeviewapplet.JTreeViewAppletMain.class"
name     = "TreeView"
id       = "TreeView"
hspace   = "0"
vspace   = "0"
align    = "top"
archive = "/Project/HTML/ABC/XYZ.jar,/Project/HTML/ABC/ABC.jar"
MAYSCRIPT>
+<PARAM NAME="onSelected" VALUE="onSelect_Handler">+
+<PARAM NAME="onFinishNormalize" VALUE="onFinishNormalize_Handler">+
+</Applet>+
Here is the snippet, whcih have been changed to <OBJECT> tag so as to support HTML5 in future:
+<OBJECT type=" application/x-java-applet"+
style    = "position:absolute;border:0px;left:184;top:95;height:180;width:364;"
name     = "TreeView"
id       = "TreeView"
hspace   = "0"
vspace   = "0"
align    = "top"
+>+
+<PARAM name="code" value=”jtreeviewapplet.JTreeViewAppletMain.class”>+
+<PARAM name="codebase" value="/Project/HTML/ABC/">+
+<PARAM name="archive" value=" XYZ.jar">+
+<PARAM name="archive" value=" ABC.jar">+
+<PARAM name="scriptable" value="true">+
+<PARAM NAME="onSelected" VALUE="onSelect_Handler">+
+<PARAM NAME="onFinishNormalize" VALUE="onFinishNormalize_Handler">+
+</OBJECT>+
After changing the *<applet>* tag to *<object>* tag , my applet itself is not loading and it gives class not found exception for jtreeviewapplet.JTreeViewAppletMain.class.
(Note: For both working and not working condition, I am using latest JDK 1.7 update 9 for compiling the code and in my system I am having latest JRE1.7 update 9 to run the applet code. I am using InternetExplorer 8 and InternetExplorer 9 browser)
Can anybody help me to find out where I am going wrong?
Edited by: 975931 on Dec 12, 2012 1:24 AM

You might want to stick to the documentation:
http://docs.oracle.com/javase/tutorial/deployment/index.html
and use the deployment toolkit.
PS: use \ tags when posting anything code related. That makes it readable and it keeps the forum from trying to interpret it.

Untagged physical object must be assigned to a tagged parent object   ?

Hi friends ,
I am using Auto-ID Test tool as simulattor of Device Controller . When i tried to trigger Tag commissioning from AII , I have sent the proper informations like GTIN , Device Controller ID , command etc.,
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Hi Michael,
Thank you very much for your valuable answer . But, i stuck up   at the printer assignment .
My question is
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Once agin thanks for the good reply .
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Explicitly extending the Object class

Hi Everyone,
I am aware that every object that is running inside a JVM inherits from class Object implicitly. Recently I have come across some code that explicitly extends the Object class, is there any advantage in doing this, please see the code snippet below:
public class MyClass extends Object{}Thanks heaps for your assistance.
Regards
Davo

I've even seen a
method that was declared "throws NullPointerException"shouldn't it have been "throws java.lang.NullPointerException" ...
- I almost cried. Yes, thats truly a terrible habit :(
a distant cousin of that habit is one I have noticed where the developer
is totally unable to name anything appropriately..
to print some things to the screen: "loadData"
to print things to screen again: "getInformation" *(note: did not 'return' anything).
... :(

Custom Tag using object as an attribute.

I have read up on trying to pass an object as an attribute to a custom tag.
Is it true that the only way to do this is to put the object, using a "key name" in the pageContext
Then in the custom tag, set an attribute equal to the "Key Name"
Then in the TagHandler, to do a lookup using the "Key Name"
We can not just past objects into the attribute?
And what is this about using EL or JSP2.0
sorry sort of new to the whole game.

Certainly you can pass objects to tags.
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If you look at the JSTL library, it uses the EL and passes in objects all the time. However the EL actually accesses the page/request etc attributes as its variable space, so you are still technically using attributes.
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Explicitly destroy an object in ABAP

Hi,
i like to destroy an Object explicitly. After the paricular statment the object must be destroyed.
if i set the reference of the object to null.when the object will be deleted? immediately or during automatic garbage collection.
Thanks and regards,
Prakash.

Hi,
you can do in OLE also.
INCLUDE OLE2INCL.
DATA EXCEL TYPE OLE2_OBJECT.
CREATE OBJECT EXCEL 'Excel.Application'.
FREE OBJECT EXCEL.
in OO ABAP
FREE OBJECT <b>OBJ</b> .
here OBJ is object reference to some class.
Regards
Vijya

Applet tag and Object tag.

Hi All,
My application is hanging which is using Applet.I have specied in IE settings to use Sun's JVM[plug in].Applet tag is now depricated they [W3c] recommend to use Object tag for IE.Is my problem somewhere related to this?what difference does it make.?Please help me its very urgent.
Cheers:
Akash.

Currently the applet is running through Applet tag.my application is using As400 emulator tn5250j which i am showing through Applet.The second frame is showing images. After entering data in As400 screen i am submitting data through submit button which is on second frame.but after submitting applet screen got hung.dont know the reason code seems to be fine.no memory leakages.
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JSP tags as object constructors?

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It does not.
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Hi PT,
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Conversion of files to PDF/A

I have been spending a lot of time lately trying to ensure that an important document can be 'archived', i.e. opened at a later date looking exactly as it should, without relying on external files (e.g. fonts) not embedded in the PDF. Essentially this means making the PDF PDF/A compliant (specifically PDF/A1b is sufficient for me). I created the original file (not PDF/A-compliant) for printing with Acrobat 7 Pro (v7.1.0).
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—DIV

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Can anyone please help me. This is very Urgent for me.
Thanks & Regards,
Shiva.

thanks.
i am giving my problem clearly. i have one applet. Previously i am loading the applet in my html page using object tag like this...
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<PARAM NAME="CODE" VALUE="com.adp.base.applet.PriceGrid.class" >
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this post already this repeating with this goes 2 times in
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How do i destroy an object explicitly ?

I need to explicitly destroy an object ... how do i do it ?
1) set object to null
2) call finalize on the object
3) ur suggestion pls...

I need to explicitly destroy an objectNo, you don't.
... how do i
do it ?You can't.
1) set object to nullObjects are never null. Only references can be null. If you set the only reachable reference to the object to null (or to any value other than pointing at that object), then the object becomes eligible to be garbage collected. When--or if--it actually gets cleaned up is beyond your control, but it's guaranteed to happen if the memory is needed.
2) call finalize on the objectNo. Never call finalize. The GC calls it for you. (And you should rarely if ever override finalize.)
3) ur suggestion pls...Read up on Java's garbage collection so that you understand why you don't need to do this.
This article is about something else, but it starts off with a decent intro to GC. You can also google for java garbage collection tutorial or something.
http://java.sun.com/developer/technicalArticles/ALT/RefObj/

Explicitly tagging an object as unused

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