BufferedReader bf; is this also treated as instance variable?

hi i m just now finished my assignment and doing documentation
and i got a single line here
BufferedReader bf; //instance variable
constructor{
bf = new BufferedReader(new InputStreamReader(System.in));
}and now i m doing documentation suddenly i got confused whether i should
write this as instance variable or not. should i?? or shouldn't i
i think this is obejct,,,,,,,but..i think it is instance variable as well..coz
it is located in the class scope..confusing.....
or not..

hi i m just now finished my assignment and doing
documentation
and i got a single line here
BufferedReader bf; //instance variable
constructor{
bf = new BufferedReader(new
w InputStreamReader(System.in));
}and now i m doing documentation suddenly i got
confused whether i should
write this as instance variable or not. should i?? or
shouldn't i
i think this is obejct,,,,,,,but..i think it is
instance variable as well..coz
it is located in the class scope..confusing.....
or not..Okay, first of all constructor {} isn't valid Java syntax, I'm assuming you just used it for brevity. Second, yes bf is an instance variable because it's not a) static (class-) variable or b) local variable.
If you thought instance variables refer only to primitives (int, byte etc.) you're wrong. Object references can also be instance variables.
So yes, it is both an object reference and an instance variable.
Sincerely,
Jussi

Similar Messages

What's the difference between global variables and instance variables?

hi im just a biginner,
but what is the difference between these two?
both i declare them above the constructor right.
and both can access by any method in the class but my teacher said
global variables are not permitted in java....
but i don't know what that means....and i got started to confuse these two types,,
im confusing.......
and why my teacher said declaring global variables is not permitted,,,,,,
why.....

instance variables are kindof like Global variables. I'm not surprised you are confused.
The difference is not in how they are declared, but rather in how they are used.
There are two different "styles" of programming
- procedural programming.
- object oriented programming.
Global variables are a term from Procedural programming.
In this style of programming, you have only one class, and one "main" procedure. You only create one instance of the class, and then "run" it.
There is one thread of control, which goes through various methods/procedures to accomplish your task.
In this style of programming instance variables ARE "global" variables. They are accessible to all methods. There is only one instance of the class, and thus only one instance of the variables.
Global variables are "bad" BECAUSE you can change them in any method you like. Even from places that shouldn't have to. Also if you use the same name as a global variable and a local variable, you can cause great trouble. This can lead to very subtle bugs, as the procedures interact in ways you don't expect.
The preferred method in procedural programming is to pass the values as parameters to the methods, and only refer to the parameters, and local variables. This means that you can track exactly what your method is doing, and what it affects. It makes it simpler to understand. If you use global variables in your methods, it becomes harder to understand.
So when are instance variables not global variables?
When you are actually using the class as an Object, rather than just a program to run. If you are creating multiple instances of an object, all with different values for their instance variables, then they are not global variables. For instance you declare a Person object with an attribute "firstname". Your "main" program then creates many instances of the Person object, each with their own "firstname"
I guess at the end of all this, it comes down to definitions.
Certainly you can write procedural code in java. You can treat your instance variables, for all intents and purposes like global variables.
I can only think to show a sort of example
public class Test1
   User[] users;
   public void printUsers(){
     // loop through and print all the users
     // uses a global variable
      for(int i=0; i<users.length; i++){
        users.printUser();
public void printUsers(User[] users){
// preferred method - pass it the info it needs to do the job
for(int i=0; i<users.length; i++){
users[i].printUser();
public Test1(){
User u1 = new User("Tom", 20);
User u2 = new User("Dick", 42);
User u3 = new User("Harry", 69);
users = new User[3];
users[0] = u1;
users[1] = u2;
users[2] = u3;
printUsers();
printUsers(users);
public static void main(String[] args)
new Test1();
class User{
String firstName;
int age;
public User(String name, int age){
this.firstName = name;
this.age = age;
public void printUser(){
// here they are used as instance variables and not global variables
System.out.println(firstName + " Age: " + age);
Shit thats a lot of typing, and I'm not even sure I've explained it any good.
Hope you can make some sense out of this drivel.
Cheers,
evnafets

Scope of instance variables in servlets..

Hi all,
          Sorry for asking a dumb question..
          What is the scope of instance variables in a servlet? Is the scope is
          limited to thread?
          In other words, in the following example, i am setting "testStr", in one
          request and when i tried to access the same instance variable from another
          request, i am getting it as null. Does it mean instance variable is limited
          to that particular thread/request?
          thanks in advance..
          -ramu


Oops ... I had misunderstood and had the problem backwards ;-)
          > Is it known behavior? With registered servlet its working fine (a
          > instance variable is shared by all requests)
          I believe so; I typically deploy in a WAR so have not seen the problem that
          you describe. Servlets can be reloaded, so what you saw could have been
          caused bye a date/time mismatch between the .class file and the server's
          current time. On the other hand, that could be how WebLogic works.
          Peace,
          Cameron Purdy
          Tangosol, Inc.
          http://www.tangosol.com
          +1.617.623.5782
          WebLogic Consulting Available
          "Ramu" <[email protected]> wrote in message
          news:[email protected]...
          > Hi Purdy,
          >
          > I got it. I am testing the servlet as a unregistered servlet, which is
          > creating instance for every new request!!!, which created this whole
          > confusion. Is it known behavior? With registered servlet its working fine
          (a
          > instance variable is shared by all requests)
          >
          > > What theory? ;-) Instance variables are on the object, and the object
          can
          > > be used by multiple threads, thus allowing multiple threads to access
          the
          > > same instance variables.
          > what i mean by theory here is, all instance variables in servlet should
          be
          > shared by all requests. Now i got it sir.
          >
          > Thank you..
          > -ramu
          >
          >
          > >
          > > Peace,
          > >
          > > --
          > > Cameron Purdy
          > > Tangosol, Inc.
          > > http://www.tangosol.com
          > > +1.617.623.5782
          > > WebLogic Consulting Available
          > >
          > >
          > > "Ramu" <[email protected]> wrote in message
          > > news:[email protected]...
          > > > Hi,
          > > >
          > > > > No, an instance variable in a servlet class is not limited to a
          > thread.
          > > > There
          > > > > is exactly one copy of the servlet created in memory and all
          requests
          > > pass
          > > > > through the same instance, thus sharing any instance variables. A
          > > couple
          > > > of
          > > > > things to remember:
          > > > I totally agree with you, But i am wondering why my sample servlet(i
          am
          > > > attaching the file) is not sharing the instance variables across
          > > > threads/reqs. (in 1st request set some string to "testStr" instance
          > > > variable, in next request if you read the same instance variable, you
          > will
          > > > get null!!)
          > > > Our current code is having instance variables. But right now we are
          not
          > > > getting any problems. But as per theory, instance variables should be
          > > shared
          > > > across threads/requests..
          > > >
          > > > Any how we are changing our code to remove all instance variables.
          > > >
          > > > thanks,
          > > > -ramu
          > > >
          > > > >
          > > > > 1.) Using instance or class variables in servlets that are not
          > read-only
          > > > is not
          > > > > a good thing to do. This makes the servlet not thread-safe. To
          > > maintain
          > > > > variables across requests, sessions, etc., use the servlet-defined
          > > objects
          > > > to
          > > > > store the state (e.g., request, session, etc.).
          > > > >
          > > > > 2.) If you modify the servlet class on disk, WebLogic will reload
          the
          > > > servlet
          > > > > class thus discarding the old instance and creating a new one (of
          > > course,
          > > > this
          > > > > depends on some configuration parameters for servlet reloading).
          > > > >
          > > > > Hope this helps,
          > > > > Robert
          > > > >
          > > > > Ramu wrote:
          > > > >
          > > > > > Hi,
          > > > > > thanks for quick reply.
          > > > > > I am not at all using SingleThreadModel. See the following code.
          > > > > > In first request i am passing "abc" value to testStr. But in
          second
          > > > request,
          > > > > > I am getting null for testStr in second request. It looks like
          (for
          > > me)
          > > > for
          > > > > > non single threaded model also, scope of instance variables is
          > > limited
          > > > to
          > > > > > Thread/Request.. But as per theory, because its not single
          threaded
          > > > model,
          > > > > > only one instance should be there AND testStr(instace variables)
          > > should
          > > > be
          > > > > > shared across the all threads. But i am not able see that
          behaviour
          > > > here.
          > > > > > But if declare instance variable as static, o am able to share
          it
          > > > across
          > > > > > all threads/requests.
          > > > > >
          > > > > > note:
          > > > > > From browser i am setting testStr to "abc" with URL like
          > > > > > "localhost/test1?testStr=abc"
          > > > > > And 2nd req from browser is like "localhost/test1" (on server
          > output
          > > i
          > > > am
          > > > > > getting null for testStr)
          > > > > >
          > > > > > Any ideas?
          > > > > >
          > > > > > thanks,
          > > > > > -ravi
          > > > > >
          > > > > > import java.io.*;
          > > > > > import javax.servlet.*;
          > > > > > import javax.servlet.http.*;
          > > > > >
          > > > > > public class test1 extends HttpServlet
          > > > > > {
          > > > > > public String testStr;
          > > > > >
          > > > > > public void doGet (HttpServletRequest req, HttpServletResponse
          res)
          > > > > > throws ServletException, IOException
          > > > > > {
          > > > > > doPost(req, res);
          > > > > > }
          > > > > >
          > > > > > public void doPost (HttpServletRequest req,
          HttpServletResponse
          > > res)
          > > > > > throws ServletException, IOException
          > > > > > {
          > > > > > try {
          > > > > > res.setContentType("text/html");
          > > > > > PrintWriter out = res.getWriter();
          > > > > > if(req.getParameter("testStr") != null)
          > > > > > {
          > > > > > testStr = req.getParameter("testStr");
          > > > > > System.out.println("set testStr = " + testStr);
          > > > > > }
          > > > > > else{
          > > > > > System.out.println("get testStr = " + testStr);
          > > > > > }
          > > > > >
          > > > > > }
          > > > > > catch(Exception e){
          > > > > > e.printStackTrace();
          > > > > > }
          > > > > >
          > > > > > }
          > > > > > }
          > > > > >
          > > > > > "Cameron Purdy" <[email protected]> wrote in message
          > > > > > news:[email protected]...
          > > > > > > Yes or no, depending on if your servlet implements
          > > SingleThreadModel.
          > > > > > >
          > > > > > > See the servlet 2.2 spec for documentation on how many instances
          > of
          > > a
          > > > > > > servlet will be created. See the doc for the SingleThreadModel
          > > > interface.
          > > > > > >
          > > > > > > Peace,
          > > > > > >
          > > > > > > --
          > > > > > > Cameron Purdy
          > > > > > > Tangosol, Inc.
          > > > > > > http://www.tangosol.com
          > > > > > > +1.617.623.5782
          > > > > > > WebLogic Consulting Available
          > > > > > >
          > > > > > >
          > > > > > > "Ramu" <[email protected]> wrote in message
          > > > > > > news:[email protected]...
          > > > > > > > Hi all,
          > > > > > > >
          > > > > > > > Sorry for asking a dumb question..
          > > > > > > >
          > > > > > > > What is the scope of instance variables in a servlet? Is the
          > scope
          > > > is
          > > > > > > > limited to thread?
          > > > > > > >
          > > > > > > > In other words, in the following example, i am setting
          > "testStr",
          > > in
          > > > one
          > > > > > > > request and when i tried to access the same instance variable
          > from
          > > > > > another
          > > > > > > > request, i am getting it as null. Does it mean instance
          variable
          > > is
          > > > > > > limited
          > > > > > > > to that particular thread/request?
          > > > > > > >
          > > > > > > > thanks in advance..
          > > > > > > >
          > > > > > > > -ramu
          > > > > > > >
          > > > > > > >
          > > > > > > >
          > > > > > >
          > > > > > >
          > > > >
          > > >
          > > >
          > > >
          > >
          > >
          >
          >

JSP and Instance Variables

I have some questions about JSP presentation (Interactive Component Call in Screenflow):
- Only BPM Objects are possible to be mapped in JSP?
- Is possible to map two or more BPM Objects to the JSP?
- What is the difference of mapping using the variable "attributes" in argument mapping and the option "Select BPM object variable" in main task of Interactive Component Call activity?

I seem to be having a similar problem.
If I include this fragment, for an instance variable called "contacts" which is a BPMObject of type "ITSSContactRequest".
<%
Object r = request.getAttribute("contacts");
Class cl = r.getClass();
out.println(cl.getName());
%>
I get the following output:
xobject.ITSSContactManagement.ITSSContactRequest
and I can access the object via reflection:
<%
Object r = request.getAttribute("contacts");
Class cl = r.getClass();
out.println(cl.getName());
Method getGeneralContacts = cl.getMethod("getGeneralContacts", null);
Object rv = getGeneralContacts.invoke(r);
%>
and access the rv variable accordingly.
However, if I try and cast the variable directly:
<%
Object r = request.getAttribute("contacts");
Class cl = r.getClass();
out.println(cl.getName());
xobject.ITSSContactManagement.ITSSContactRequest rq = (xobject.ITSSContactManagement.ITSSContactRequest)r;
%>
I get the following error message:
"The task could not be successfully executed. Reason: 'fuego.web.execution.exception.InternalForwardException: UnExpected error during internal forward process.'.
See log file for more information [Error code: workspace-1258985548580] "
The same error occurs if I try and import the object via
<%@ page import="xobject.ITSSContactManagement.ITSSContactRequest" %>
Thanks for any help.

TS3968 This also affect DVD Studio Pro and compressor.

This also affect DVD Studio Pro and compressor, that were useless after upgrading to Snowleopard. Prokit 7 solved the problem. How come it doesn't come automatically with software update? Lost two hours on a crashed DVD project and looking for this very simple solution. Love you Apple, but this time you let me down...
After updating to Snowleopard, FCP comes up with a warning about unsupported enablerfiles during start-up. Prokit 7 didn't solve that problem. Anybody...?

Right on, Eric.
I'm a devoted Windows man, but I must say that DVDSP is the best DVD authoring software I've tried so far.
As far as compressor goes, it depends what program you are exporting from and for what purpose. There are many options in there and I for instance found out that using something like a Photo JPEG compression rather than a DV PAL setting for a project that was all in DVD PAL gave a better output.
Compressor is a pretty big program and by trying different things out, you can probably find what you need.
Sounds like there could be a problem with your computer if everything comes out as crappy as you say...?
Good luck figuring it out or make your mpegs on PC's TMPGEnc. (He-he... )
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When I open a pdf document from my dropbox to view it, the document shows up blank, even though it is filled out. This also happened with pdf documents that have been e-mailed to me.

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Unable to get the composite instance for the invocation. This could be because instance has not yet been created or because the audit level for the SOA infra has been set to Off

I am on Oracle 11.1.1.7 BPM suite on W8 64 bit. I can't launch the flow trace and get the error "Unable to get the composite instance for the invocation. This could be because instance has not yet been created or because the audit level for the SOA infra has been set to Off". I have set the audit level to development at the soa-infra>SOA Administration> Common Properties > Audit level set to development and Capture Composite Instance State is Checked.
Can somebody advice.
Thanks

Can you please confirm me the following steps...
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Thanks,
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On 3G we cannot send emails from either our iPhones or iPad and this also happens with some WiFi connections but not all. Yet we can always send emails from our Hotmail Email account. What is causing this and what do we need to do to resolve it?

On 3G we cannot send Business emails from either our iPhones or Ipad and this also happens with some WiFi connections but not all. Yet we can always send emails from our Hotmail Account using both 3G and WiFi.
We bought the iPhones and Ipad so that we could send emails while we are out of the Office, but we are not able to do this unless we can find a WiFi connection. Incoming emails are fine. We use IMAP, for Business emails just incase this is relevant and I know that Hotmail is POP3.
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When I try to open Adobe Reader, it just opens a gray page and then closes by itself. This also appl

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THanks

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I can't access my dial pad to make calls. The last few days when I go to the phone a pop up appears that says "unfortunatly contacts has stopped working" after pressing ok to remove the pop up, it goes back to the home screen. This also happens when I

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When I edit photo's in Iphoto on my ipad2, it decreases the resolution. Why does this happen and does this also happen on a macbook air?

I have made pictures on high resolution with a Canon 100D camera, which means the pictures are 5-6 MB.
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Does anyone know why Iphoto decreases the resolution of my pictures when I edit them?
And does this also happen with Iphoto on a macbook air?
Thank you.
Onno

I have made pictures on high resolution with a Canon 100D camera, which means the pictures are 5-6 MB.
Are the photos raw photos or jpeg? When you edit raw photos in iPhoto on your iPad, the raw image will not be processed, only the embedded jpeg. That will reduce the resolution of the image considerably.
But when I edit them on my Ipad2 in Iphoto it decreases the size and resolution of the pictures to about 0.5MB
How do you save he edited version after editing? That will determine, if the image will be scaled down,
For a full-resolution edit you need to share the edited photo to the Camera Roll,
see this help page: Edit a photo
If you edit a photo in the iPhoto Camera Roll album, the edited photo automatically appears in the Camera Roll on your iOS device, at the resolution of your device. If you want a full-resolution version of the edited photo sent to the Camera Roll, tap and tap Camera Roll. The full-resolution photo appears in the Camera Roll, and is transferred to your computer when you sync the Camera Roll with your computer.
And does this also happen with Iphoto on a macbook air?
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I am having a problem where pdf files on the web (i.e., links in a Word doc) open after an extended time and only as gobbldygook ( a file containing a series of characters and letters that make no sense). This also happens for another Mac user coworker

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Just adding more info - MacBookPro running 10.5.8 and using Safari as the browser. The problem comes and goes - sometimes the linked Word files will open OK, n others its just a strring of crazy characters...

The last update failed on my window 7 pc, resulting in me having to try it manually download and install, this also failed leaving my I tunes not working, I tried restore back to a safer date, but every time it tried to update it failed. eventually i

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after mixing a project i select bounce and burn the disc that is burned plays on any cd player but when i try to burn the wav or mp3 file that was created the resulting disc will only play in a computer this also happens with video projects help please are there any settings i need to alter as it seems the wav or mp3 file i ceated is being converted to a data file somewhere between the folder and disc drive

Same thing for a movie file.. If you want to play back the movie via a DVD and a DVD player you must create a Movie DVD and not just burn files to a data DVD... as Data DVDs are just storage devices for files and therefore will only work with computers...
Movie DVDs are special formats that include things like menus and special file formats.. so they can playback via a DVD Player...
You will need a 3rd party DVD Burning app like Toast which is what i actually use.... or the more popular DVD Creator app...to create and then burn a Movie DVD that will playback on a DVD Player....
https://answers.yahoo.com/question/index?qid=20101220205435AA70beb

HT1420 since upgrading to a domain the computers had to be re authorised for itunes, is there a way to deauthorise compters without waiting till the next deauthorise all? this also happens when upgrading from windows 8 to 8.1.

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BufferedReader bf; is this also treated as instance variable?

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