What happen when i compile a java prog.

I, to an extend know how to code using java. However I don know what really happens after compiling a java prog and what happens when i run it.. what is JVM, JDK, JIT etc., means.. What is a class file and a jar file and a war file.. I'm confused.. ANy help is really appreciated..
Thanks in advance..
regards.

Java source is compiled into "portable byte code" (a class file).
The JVM (virtual machine) interprets the "portable byte-code" into "machine instructions"... The actual instructions may vary from platform to platform, but the contract is they will allways have the same effect.
JIT stands for "Just In Time"... as usually means "JIT-compiler"... which is fancy pants name for an interpreter.
Google will tell you more.

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What happens when I compile a block

Dear buddies,
I am going to compile a script written by my manager. It starts with declare -- begin -- end --
Just by compiling it, will I be running the block? or how does it work? I am using PL/SQL Developer
Could someone guide me.
Thank You!
Nith

P. Forstmann wrote:
I don't know how PL/SQL Developer works but according to Oracle documentation it seems that you can only compile and run at the same time a anonymous PL/SQL block. You can compile only (or more correctly, just do a parse). E.g.
SQL> --// basic SQL parser
SQL> create or replace procedure SQLparse( statement varchar2 ) is
2          cur     number;
3 begin
4          cur := DBMS_SQL.open_cursor;
5          DBMS_SQL.parse(
6                  cur,
7                  statement,
8                  DBMS_SQL.native
9          );
10          DBMS_SQL.close_cursor( cur );
11 end;
12 /
Procedure created.Calling this will create a cursor in the Shared Pool. Nothing will however execute as yet. The cursor will be shareable and reusable (and should be using bind variables to improve both these). E.g.
SQL> --// parse a cursor
SQL> exec SQLparse( 'begin /* BLOCK */ :s := to_char(sysdate); end;' );
PL/SQL procedure successfully completed.
SQL>
SQL> --// check the shared pool for the cursor that
SQL> --// was created
SQL> select executions, sql_text from v$sqlarea where upper(sql_text) like 'BEGIN /* BLOCK */%';
EXECUTIONS SQL_TEXT
         0 begin /* BLOCK */ :s := to_cha
           r(sysdate); end;
SQL>
SQL> --// check reusability
SQL> var s varchar2(20)
SQL> begin /* BLOCK */ :s := to_char(sysdate); end;
2 /
PL/SQL procedure successfully completed.
SQL>
SQL> select executions, sql_text from v$sqlarea where upper(sql_text) like 'BEGIN /* BLOCK */%';
EXECUTIONS SQL_TEXT
         1 begin /* BLOCK */ :s := to_cha
           r(sysdate); end;
SQL> So this works pretty much the exact same way as with ordinary SQL. A cursor is created in the shared pool. This cursor contains both the source code and compiled version. It will be reused when the same source code hits the database while the cursor exists. Etc.
The only real difference is that instead of the cursor containing SQL code, it contains PL/SQL code. The rest is identical - and neither the SQL nor the PL/SQL (source and compiled) code for this is stored permanently in the database (as would be the case with stored procedural code).

What happened when multiple audio players start at the same time?

Hi,everyone!
I am developing a game, using JMF to play sound.
These sound are stored in mp3 files.
In order to decode mp3 files, I installed JMF and mp3-plugin( jmf-2_1_1e-windows-i586.exe , javamp3-1_0.exe).
In the Game, a background music play back repeatly.When EndOfMediaEvent happened, I setMediaTime(new Time(0)) and then start().It works well.
There are several sound-effects,may start at any time,
so 2 or more sounds may play back at the same time,
and then Strange things happened.
Those sound-effects, usually short, can not play back inextenso.
They lose some beginning part, the length of the part is not constant.
i.e. Audio should start at MediaTime 0, but now they start at MediaTime x, x >= 0,
not only that, sometimes, Audio process bar runs, but no sound heared.
I do not know what is happening.
So please help me, thanks a lot.
The way that I use Players:
initialize:
create realized players from mp3 files
prefetch them
finalize:
deallocate not null players
then close them
using:
player.setMediaTime(new Time(0))
then player.start()
My Environment:
Windows XP, java 1.4.10, JMF2.1.1, MP3-plugin1.0

This is very strange, difficult to guess the cause... never had such an issue. Normally when the object to which the audio is attached disappears the audio stops. So in your case going to a next slide should stop the audio of the previous slide. Same with object audio.
Do you have the different audio clips (one per slide) in the Library? Could you try to delete the audio on the slide and drag it again from the Library to see if you have the same result? And what happens when you attach the audio clip to an object on the slide (you can create a totally transparent rectangle with no stroke that will not be visible to attach the audio).
Lilybiri

What happens when an iPod is synchronized with an iTunes library that is bigger than the available space on the iPod?

What happens when an iPod is synchronized with an iTunes library that is bigger than the available space on the iPod? I did this some time ago. On screen was shown available space somewhat less than 120 GB, but maybe somewhere between 10 and 20 GB more in the library. I had to get the iPod updated anyway, so I did proceed. However, afterwards the total content of the library was only about 110 GB. Now I wonder what did actually happen. Was the first sign only corrected for double copies of the same files or lost files or where files deleted from iTunes? And if files where deleted from iTunes, were they also deleted from my computer?

Same as you would if you bought a pc; copy everything from your old computer to your new one. Then you can just sync everything from the new computer, as you did with the old one.

What happens when multiple users access the same servlet?

Do the users share all the same resources? Or is a new process generated for each user? I have a servlet that builds a string to return to the user and I only have myself to test, so I can't really see what happens when many users access the servlet. Is there a possibility that the string will get screwed up, like when dealing with multiple threads, or do all the users get their own resources and I don't have to worry about that?

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I want to change my Apple ID because I have a new email address, but what happens when someone tries to facetime me using my old Apple ID?

I want to change my Apple ID because I have a new email address, but what happens when someone tries to facetime me using my old Apple ID? Will they still be able to contact me on facetime using my old Apple ID?

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I recently downloaded Parallels 9 to my imac so I could install Windows 7 Home Premium and had no trouble everthing is working fine the only question I have is is there a benefit to migrating the 2 together and what happens when I do Thanks. Ricco

I recently downloaded Parallels 9 to my imack so I could install Windows 7 Home Premiumwith no problem and everthing is working fine, and I was thinking of Migrating the 2 2 and was wondering what benefits there would be and what happens when I do.

Windows 7 will peer down through the VM and remember what hardware the VM is installed on. Migrate the VM to different Mac hardware, and on first boot, Windows 7 will advise you that you are not using genuine Microsoft Windows. It will then treat you as though it believes you misappropriated it.

Time Machine backup created on Mac with a large hard disk. What happens when restore to MacBook Air with small SSD drive?

What if a Time Machine backup was created on a Mac with a large hard disk, e.g. 500GB iMac - and I buy a new MacBook Air with a small SSD hard disk e.g 128GB. What happens when I need to use the larger Time Machine file to set up the new MacBook Air? What happens to all those files that can't fit on the smaller SSD drive?

It is not the HD size, but rather the size of the data it contains. If you right-click your 500GB drive and select "Get Info" you can see how much is actually being used.
Naturally if you are using more space than the new drive has, then you have to make some choices about what you want to keep and what you want to keep archived.
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What happens when I restore data to a non-factory set iPhone?

Okay, another iCloud question. What I did was basically delete a game, start a new one, and now I want my old game back (saved to ICloud). What happens when I restore full data to a non-factory set iPhone? Will it overwrite current data? Will it delete everything? I just want to know, I'm such an iOS noob. :-/

A restore is all or nothing.
If a backup is restored to the device, ALL data currently on the device is wiped and replaced with the data from the backup.
Restoring a backup to get one saved game back seems rather extreme and silly.

What happens when HTTPS communication fails during certificate check?

Hello Experts,
I have a scenario where a Bapi functionality(server proxy) is exposed as a webservice .
So scenario will be SOAP -> XI -> Proxy (calls a BAPI)
Here we are going to use HTTPS (SSL).
I would like to know :
What happens when a check for certificate validation fails in XI? It may be due to invalid certificate, expired certificate or a request from unauthorised user-
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Thanks in Advance!!
Regards,
XI Queries.

Hi Abhishek,
Thanks for the reply. I will keep this in mind and design the scenario & error handling accordingly.
Appropriate points awarded
Kind regards,
Xi Queries.

What happens when max job limit of few RAS server is reached?

Hi, I would like to know what happens when max job limit of server is reached. I know that we need to increase the job limit but my question is a bit different.
We have 7 RAS per servers. I got this message "The maximum report processing jobs limit configured by your system administrator has been reached" on 4 RAS servers but not all 7. I am tracking servers using PIDs on WIndows server 2003.
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OR
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We are doing 3000 users performance testing on 21 RAS servers.
We are on BOXI R2 SP3 on IIS and opening crystal reports using .NET SDK.
Thanks,

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What happens when Time Machine starts to fill up a drive?

Using Time Machine on a partitioned External HD has been an absolute snap! I love the app. My main disappointment with it is that it has no literature on HOW it works, and no real ways for me to set different controls for it other than on and off.
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What happen when Database in Backup Mode?

Hi,
What happen when we kept database in backup mode, Means using command 'Alter database Begin Backup';
Thanks...
Asit

jgarry wrote:
EdStevens wrote:
jgarry wrote:
What do you think of the snapshot backup on page 22 of [url http://en.community.dell.com/techcenter/storage/w/wiki/2638.oracle-11g-backup-and-recovery-using-rman-and-equallogic-snapshots-by-sis.aspx]this paper? (No sarcasm, I'm curious about these snap solutions in general. Though I am really down on Dell for what turned out to be a brain-damaged laptop I got for my wife.)
Well, you can't really make a judgement about a company's enterprise products based on an experience with their consumer products.What if it came from what they call a business products catalog? They intermingle laptops with servers.
Don't know, in general. I do know that for Dell there is a distinct difference between their decidedly consumer laptops (Inspiron) and their "business" Lattitude series. I know that at my last job we had a lot of rock solid HP equipment (servers and SAN) - vs. an HP laptop I had that was trouble from Day One. I'm sure there is a point in desktops and laptops the line can get blurred, but in the case of the OP, he was no where near that fuzzy line.
>
>>
Perhaps I can find time to read the white paper over the weekend ....

I have both the 250 gb high performance hard drive and a 1 ter byte hard drive. What happens when the 250 gb hardrive is full?

I have both the 250 gb high performance hard drive and a 1 ter byte hard drive. What happens when the 250 gb hardrive is full? This on Imac desktop

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AND keep 50-100 GB of free space on a startup drive to allow proper function of virtual memory in all OS X versions from 10.5x to current versions.
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I try and keep all boot drives between 50 and 60% of capacity.
Beyond 60% and up to 90% capacity, seek times increase almost exponentially; performance suffers.

Lost my iPod, remotely locked it through iCloud. What happens when the battery goes out?

Hello!
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What happen when i compile a java prog.

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