System.out.println makes things work fine????

I have a case where vector hasto be populated based on some condition. It is in a for loop.But it throws null pointer exception when i try to access the elements in the vector as its empty.So to check that i gave a System.out.println to check the values at the point of inserting the elements into the Vector.At this point it starts working fine.I got this problem 2-3 times.I checked if i missed out something.But that was not the case.A System.out.println was causing the values to be inserted into the vector. I then removed the SoPs and tried.It worked fine.Any Idea??????????this is causing headache for me.I am using eclipse and tomcat4.1 with jdk1.4.2

Honestly roshan, "I checked if i missed out something" and similar just isn't
enough.
You need to post code. Not 1500 lines but a small example that others can
compile and run to observe the behaviour that you observe.
Constructing such an example often helps in solving a problem. If the problem
goes away when you remove code that contains or calls the method in question
that's a sign of where the problem may lie (Even if that code seems to be
irrelevent).
The task of constructing a small example like this is not always easy: but it's
useful for you and essential for others.

Similar Messages

System.out.println () is not working properly

Hi, Why does this happens:
Object temp=null;
System.out.println ("temp is null? "+temp==null);
just prints: true
expected: temp is null? true
Why does this happens????
If I do System.out.println ("temp is null? "+(temp==null)); it works bu it should work without the pharentesis too

MelGohan wrote:
Hi, Why does this happens:
Object temp=null;
System.out.println ("temp is null? "+temp==null);
just prints: trueThat is odd, mine prints "false".
type Test126.java
public class Test126 {
    public static void main(String[] args) {
        Object temp=null;
        System.out.println ("temp is null? "+temp);
        System.out.println ("temp is null? "+temp==null);
}javac Test126.java
java Test126
temp is null? null
false

How use system.out.println with a Java Swing Applet?

Hi guys,
I was just wondering what can I use to view output on the Java console with a Java Swing Applet?
At the moment I'm using a JTextArea within the Applet for debugging but I want output to appear in the browser java console but system.out.println doesn't work.
I'm viewing the Swing Applet on Netscape 4.7 browser.
Any ideas?

System.out.println()s work fine! I'm guessing that your problem is that you are looking at the wrong console window!
You're using the Java Plug-in, right? On Windows, go to your Control Panel and double click "Java Plug-in". You should find a checkbox option to "Show Java Console" - make sure this is checked. Next time you fire up you JApplet, you should see a Java Console window popup.
Hope this helps!

System.out.println() in JUnit

Hi Everybody,
Can you please solve my confusion, weather System.out.println(); will work in JUnit or not.
When I wrote System.out.println in Junit i am not getting anything.
Thanks in advance
Ananda

Junit is also a java class which extends the junit.framework.TestCase.
So the System.out.println() method always works in the junit class.
Try this code:
import junit.framework.TestCase;
public class TestJUnitTest extends TestCase {
     public void testCase1() {
          System.out.println("hello");
          assertEquals(true, true);
}

Help: What can make "System.out.println" not displaying anything?

Hello,
We have Portal 10g.
I have noticed a pb on the interpretation of existing JSP pages.
I simplified the code... and I noticed that even this command doesn't work :
<%
System.out.println("Hello World");
%>
Any idea ?
Is there any security ? permission I should get ?
JSP works fine on our old 8i environment ...
Thanks in advance for your help.
Olivier

Olivier,
between 8i and 10g are aeons of time (for computer technology). As far as I recall, in 8i came with a Apache and JServ module. This supported Servlets and JSP through a special Oracle implementation. After that OC4J as a J2EE container for EJBs and Servlets/JSPs was introduced.
Using JSPs with the database installation only is not advised anymore. You can use OC4J for that. But be aware that will require some changes in the configuration and deployment of JSPs.
HTH,
--olaf

Is there a way to make system.out.println() scroll down as it goes?

I am writing a program where I want to be able to read what's printed out in the console of my IDE through System.out.println() as the program runs/after the program runs. However, right now I run the program, the message prints out, and then when I go to read it the scroll bar is all the way up so I can see only the top of the print-out (the first thing printed out). Is there any way I can get the console to scroll along with the text, kind of like floating boxes you see on various websites for various reasons? In other words, can I get it so that when I look in the console at any given moment of the program running, I am looking at the newest text printed out (the text at the bottom of the "page")? Thank you!

That would be an IDE problem and not a Java one. You could redirect output into a text file so you can read at your leisure and scroll up and down as much as you like.

32-bit JDK 7 System.out.println not working in IDE

Hi folks,
I have a 64-bit Windows 7 OS.
Due to 3rd party library/jar dependencies, i had to install the 32-bit Java JDK 1.7 and Eclipse IDE.
I also installed NetBeans.
So i have a 64-bit OS and am running 32-bit Java JDK/JRE & IDEs.
The problem I am having is that my program's System.out.println("...") statements are not outputting strings to either IDE debug console.
Executing the compiled program from a command line/prompt produces the expected string output.
The basic "Hello, World" program is enough to cause this behaviour to start occurring.
I have not manually / intentionally changed any IDE-specific Debug Console or Windows environment settings.
One caveat: This same environment has worked successfully in the past ?! Yes, this is one of those "..it worked last week & yesterday and today it isn't and i swear i didn't do anything..." issue.
Thoughts ?

Thanks for the reply.
The 64-bit versions of Java & Eclipse were installed first.
When i discovered I had to use the 32-bit versions, i un-installed the 64-bit ones & installed the 32-bits.
Even after that initial un-install 64-bit/install 32-bit process, it was working.
I have also been installing the Windows 7 64-bit OS updates when i am informed of them.
I'm not sure if any of these would affect how the Eclipse / NetBeans IDEs behave.
Behaviour has been inconsistent.
Initially it was always working.
But over the past several days, it has been working less and less.
I don't have any large data structures.
This isn't a large complicated program, couple hundred lines, so i highly doubt that i'm doing anything to the resources, but something has changed.
The main project I am working on takes command line parameters, does some initial processing, produces output using System.out.printlns [SOP] then depending on the parameters, branches into 2 different processing paths, let's call them A & B. Each of these processing paths also use SOPs. When i run the program in the IDE going thru path A, sometimes the initial SOP statements will work and the SOP statements specific to path A will also work. If i immediately change the parameters to go thru path B & re-run it, not even the initial SOP statements before the branching decision work.
I've tried doing System.flush()s too - no affect.
I haven't tried the re-direction option to a file option you mentioned yet.
It always works from a command prompt - that is telling me that the Java SOPs are working properly, correct ?
Inside an Eclipse or NetBeans IDE, SOP output to the debug console is inconsistent.
Running from a command prompt, the SOPs always work.
It'd help to know if this an IDE issue, a Java issue, a Windows 7 issue so i can narrow down where to try and correct the situation.
I have a Windows XP VM set up, i'll try running the program there and see if there's a difference.
Thanks for your reply.

System.out.println not working in Tomcat-4.1.x

System.out.println not working in Tomcat-4.1.24. Any settings has to be enabled??? I am using tomcat for Solaris

I think u can use ServletContext.log() to output info instased.

How does System.out.println(). Work inside src.zip file !

Hello guyz,
I was just wondering how System.out.println() worked so i opened up the src.zip file and checked the source code. But could not understand it. As written i remember
"out is an object encapsulated in the System class."
Thats ok. But i could not understand the code.
    public final static PrintStream out = nullPrintStream();
    private static PrintStream nullPrintStream() throws NullPointerException {
     if (currentTimeMillis() > 0) {
         return null;
     throw new NullPointerException();
    }Also when i ran the DJ Decompiler it decompiled it to this:
public class One
     public static void main(String args[])
          System.out.println("hello world");
import java.io.PrintStream;
public class One
    public One()
    public static void main(String args[])
        System.out.println("hello world");
}Also, why does it need to import PrintStream ?

Peter__Lawrey wrote:
I was just wondering how System.out.println() worked so i opened up the src.zip file and checked the source code.This value is a place holder. This value is changed as soon as enough of the JVM is initialised for printing to work.
Also, why does it need to import PrintStream ? It doesn't, but it is used in the code so DJ is including it just in case.Sorry,
But i don't understand at all.

It should work like system.out.println

hai my objective when i pass any string argument to myprint method it should work like system.out.println . but iam not getting out put . please any one help me
public void myprint(String data){
try{
byte[] bytearray = data.getBytes();
ByteArrayOutputStream bos = new ByteArrayOutputStream();
bos.write(bytearray,0,data.length());
PrintStream ps = new PrintStream(bos) ;
System.setOut(ps);
catch (Exception e){
e.printStackTrace();
}

Doesn't something seems out of order here?
1. This is not the correct forum.
2. You are writing the bytes to the ByteArrayOutputStream first and then setting to the System outputstream. Shouldn't it be the other way round?

Want the "System.out.println()" that is within the java stored procedure works?

hello
i write a java stored procedure,and put a line as "System.out.println(...)" within the procedure,after publish it,i can test it within the sqlplus by invoke following command:
SQL>set serveroutput on;
SQL>call dbms_java.set_output(....);
but when i test it within the jdeveloper9.0.3,it can't be print,why?
thank you!

You can try this:
DBMS_OUTPUT.enable(100000);
DBMS_JAVA.set_output(100000);
HTH,
Robert

Why doesn't System.out.println work for Palm?

In my Java code,
how come I don't see any output on my screen (Palm Vx) when I try this?
System.out.println("Hello World");
Where is the output really going to???

Hi,
On POSE (Palm OS emulator), the System.out.println() method output is a file called STDOUT.txt, filed in some directory of the emulator.
On the eal device, I think theres no output for system.out.println().
Ricardo

Strange behavior with System.out.println

I was working with the following code:
1. public class DemoChar {
2. public static void main(String args[]) {
3.
4. char buf[] = new char[50];
5. buf[0] = 'a';
6. buf[1] = 'b';
7. buf[2] = 'c';
8. buf[3] = 'd';
9. buf[4] = 'e';
10. System.out.println( buf);
11. }
12. }
if you print "buf", it really works; however if you change line 10 by :
System.out.println("--->" + buf );
The method "println()" doesn't write "--->abcde". The functionality doesn't the same. It will appear "----> [C@3e25a5"
Could you help me?
I don't understand that behavior. I am using "java version 1.6.0_07"

buf's an array and thus is an object. object's don't inherently know how to represent themselves as Strings, so you have to do other things to make sure that they print out ok. To get a char array to print well, you could use the String method valueOf(...):
public class DemoChar
public static void main(String args[])
    char buf[] = {'a', 'b', 'c', 'd', 'e'};
    System.out.println(buf); // this seems to call implicitly String.valueOf(buf)
    System.out.println("--->" + buf); // this however seems to call buf.toString() with different results
    System.out.println("--->" + String.valueOf(buf));
}Also, when posting your code, please use code tags so that your code will retain its formatting and be readable. To do this, you can will need to paste already formatted code into the forum, highlight this code, and then press the "code" button at the top of the forum Message editor prior to posting the message. You may want to click on the Preview tab to make sure that your code is formatted correctly. Another way is to place the tag [code] at the top of your block of code and the tag [/code] at the bottom, like so:
[code]
// your code block goes here.
// note the differences between the tag at the top vs the bottom.
[/code]or
{code}
// your code block goes here.
// note here that the tags are the same.
{code}Edited by: Encephalopathic on Aug 21, 2008 9:40 AM

Synchronized use of System.out.println()

So I am again at the point of part of my program running ahead of itself out of the call stack and ruining the sequence or order of printing.
I read that System.out.println() is synchronized so how may it be used to wait() until notified to continue and not ruin the output?

jverd wrote:
Always Learning wrote:
YES SIR EJP! SIR! I thank you for the assistance because using only System.out and synchronizing worked beautifully.You said you're not using multiple threads. If this is true, then there's no reason to synchronize anything. The output will appear on System.out in exactly the order you send it there.
Nos if only I could figure out dependencies to make it work with out and err.You have to stop and think about it for a minute. You know that when you call println() on either one of those two streams, the output may be buffered an not necessarily go immediately to the console. From that you can reason that if you call out.println() first, and then err.println(), that you could end up with err's buffer getting flushed first, and the output appearing on the console in a different order than that in which your code executed the calls.
You are of course not surprised by this, given that you know that out and err are completely independent and just happen to end up at the same destination in this particular case.
So, as a first guess, you might reasonably think that, since buffering is obviously the culprit here, calling flush() on each stream after each print() or println() call should eliminate the problem. In a multithreaded environment, this wouldn't be sufficient, of course, but it's a logical approach to try here.
Another tidbit to make note of is that the System class has setOut() and setErr() calls. Since you're looking at out and err in the same console, you presumably don't care about the distinction between them (which makes me wonder why you're using them both in the first place, instead of just using one). If you're just going to mush them together into the same console anyway, then you can use setOut() or setErr() to make them the same stream, and things will be ordered as you expect.Very interesting Jverd and I think there may yet be life in what I would like to do. I did not know or was not immediately aware of these things. I will give it a try.
To answer your question, I am using them both because, like logging, they are distinct in the Eclipse console (black for out and red for err). With your patch I just tried that distinction has faded but the output is sequenced the same so I do appreciate you noting this. Learn something new in Java each time I am doing a project. I considered using logging and putting errors in a window but I am not sure if I should do that; just not enough experience with it.
Edited by: Always Learning on Oct 23, 2011 9:28 AM

System.out.println not showing up in the console

Hi,
I've some System.out.println statements in a static block in a Stateless
Session Bean. I could not see these outputs in the Weblogic console. I'm
using Weblogic 5.1 Any one faced this problem before? any help is
appreciated.
Thanks & Regards,
Nithi.

Take a look in the weblogic log files they might be redirecting std out.
"Ryan LeCompte" <[email protected]> wrote:
>
Hello Nithi,
I'm all out of ideas, unfortunately! However, check out the following
links for
some possible insight into the problem:
http://groups.google.com/groups?q=System.out.println+5.1+WebLogic&start=60&hl=en&lr=&ie=UTF-8&oe=UTF-8&selm=3d3df18e%40newsgroups.bea.com&rnum=69
http://groups.google.com/groups?q=System.out.println+5.1+WebLogic&start=70&hl=en&lr=&ie=UTF-8&oe=UTF-8&selm=3977417b%40newsgroups.bea.com&rnum=71
http://groups.google.com/groups?q=System.out.println+5.1+WebLogic&start=200&hl=en&lr=&ie=UTF-8&oe=UTF-8&selm=3bc20346%241%40newsgroups.bea.com&rnum=209
Best regards,
Ryan LeCompte
[email protected]
http://www.louisiana.edu/~rml7669
"Nithi Rajan" <[email protected]> wrote:
Hi Ryan,
Thanks for your reply and sorry for the long silence. I was on vocation.
Thre problem still remains.I'm very sure that the EJB
is deployed by WebLogic as I'm able to call some methods.
and I'm also calling EJB methods from Servlet. But my
System.out.println statments work fine in the Servlet and
not inside EJB (or anyother classes used by EJB).
Any one has faced similar problems? BTW am using WebLogic 5.1
Thanks in advance,
Regards,
Nithi.
"Ryan LeCompte" <[email protected]> wrote in message
news:[email protected]...
Hello Nithi,
I find it strange that your System.out.println statements are beingexecuted from
within your servlets, but not in your stateless session bean. Are
you
positive
that your EJB is being located and deployed by WebLogic? The statementsin
your
static { } block should be executed as soon as the WebLogic class
loader
finds
the class and loads it into the JVM. I would suggest examining theconsole
and
try to determine if your EJB is in fact being deployed. Are you invokingmethods
on the EJB inside of your servlets? Are you using any logging frameworkfrom within
the EJBs which would redirect output to a file?
Best regards,
Ryan LeCompte
[email protected]
http://www.louisiana.edu/~rml7669
"Nithi Rajan" <[email protected]> wrote:
Hi Ryan,
Thanks for your reply. The setting in the weblogic.properties is
as
follows.
weblogic.system.enableConsole=true
So, that tells me that I should see all the System.out.printlns right?
(Pleasecorrect me if I'm wrong). I can see all the System.out.println
from
my
servletand not from the Session Bean (even if the System.out.println
is
outside
static block).
Please let me know your thoughts.
Thanks & Regards,
Nithi.
"Ryan LeCompte" <[email protected]> wrote in message
news:[email protected]...
Hello Nithi,
Are you sure that you don't have WebLogic configured to redirect
all
messages
to a file instead of the console? Are you able to see yourSystem.out.println
statements when placed within other methods of your stateless sessionbean? Please
be a bit more specific.
Thank you,
Ryan LeCompte
[email protected]
http://www.louisiana.edu/~rml7669
"Nithi Rajan" <[email protected]> wrote:
Hi,
I've some System.out.println statements in a static block in a
Stateless
Session Bean. I could not see these outputs in the Weblogic console.
I'm
using Weblogic 5.1 Any one faced this problem before? any helpis
appreciated.
Thanks & Regards,
Nithi.

System.out.println makes things work fine????

Similar Messages

Maybe you are looking for