System.err.println or System.out.println

while(true)
System.err.println("Exception");
The above sentences will cause the memory usage always increaing, at the end it will run out of memory.
Why?

public class Test {
public static void main(String [] args) {
while(true) {
System.err.println("Exception");
This is the whole program. It is definately a infinite loop, but it doesn't matter. Anyone can test it by changing the string value. Also, you can monitor the memory usage. It is very different between "Exception" and other strings which don't include "Exception".
I use the Jbuilder5 under NT 4.0.

Similar Messages

Out.println in jsp?

Can out.println be used in JSP? I got the following error:
I have googled that out.println cannot be used in a method declaration, which is what i've done. So what do i do from there?
C:\Documents and Settings\USER\Desktop\FOS_Menu\FOS_Menu\build\generated\src\org\apache\jsp\menu_005ftest_jsp.java:39: cannot find symbol
symbol : variable out
location: class org.apache.jsp.menu_005ftest_jsp
                        out.println("<li><a href=" + strMenuLink + ">" + strMenuName + "</a>");
                        ^
C:\Documents and Settings\USER\Desktop\FOS_Menu\FOS_Menu\build\generated\src\org\apache\jsp\menu_005ftest_jsp.java:40: cannot find symbol
symbol : variable out
location: class org.apache.jsp.menu_005ftest_jsp
                        out.println("<ul>");
                        ^
C:\Documents and Settings\USER\Desktop\FOS_Menu\FOS_Menu\build\generated\src\org\apache\jsp\menu_005ftest_jsp.java:42: cannot find symbol
symbol : variable out
location: class org.apache.jsp.menu_005ftest_jsp
                        out.println("</ul>");
                        ^
C:\Documents and Settings\USER\Desktop\FOS_Menu\FOS_Menu\build\generated\src\org\apache\jsp\menu_005ftest_jsp.java:44: cannot find symbol
symbol : variable out
location: class org.apache.jsp.menu_005ftest_jsp
                        out.println("<li><a href=" + strMenuLink + ">" + strMenuName + "</a></li>");
                        ^
C:\Documents and Settings\USER\Desktop\FOS_Menu\FOS_Menu\build\generated\src\org\apache\jsp\menu_005ftest_jsp.java:113: out is already defined in _jspService(javax.servlet.http.HttpServletRequest,javax.servlet.http.HttpServletResponse)
                    PrintWriter out = response.getWriter();
                                ^
5 errors
C:\Documents and Settings\USER\Desktop\FOS_Menu\FOS_Menu\nbproject\build-impl.xml:364: The following error occurred while executing this line:
C:\Documents and Settings\USER\Desktop\FOS_Menu\FOS_Menu\nbproject\build-impl.xml:149: Compile failed; see the compiler error output for details.
BUILD FAILED (total time: 1 second)At first i didnt declare a PrintWriter but then after i first got the error, i just threw it in. But it seems that even that part has an error too. Thanks.

Thanks! I actually thought that it was not a good idea to use it because the method i created can calls itself and it is very confusing to me. So i switched back to using normal codes html. (is it called template code?) Anyway this is a new problem that i face, should i start a new thread since its a different issue?
The new error, could it be due to the two different try and catch? (see code below)
C:\Documents and Settings\USER\Desktop\FOS_Menu\FOS_Menu\build\generated\src\org\apache\jsp\menu_005ftest_jsp.java:40: illegal start of expression
private static java.util.List _jspx_dependants;
C:\Documents and Settings\USER\Desktop\FOS_Menu\FOS_Menu\build\generated\src\org\apache\jsp\menu_005ftest_jsp.java:27: 'try' without 'catch' or 'finally'
            try{
            ^
C:\Documents and Settings\USER\Desktop\FOS_Menu\FOS_Menu\build\generated\src\org\apache\jsp\menu_005ftest_jsp.java:123: 'catch' without 'try'
                        } catch (SQLException ex) {
                          ^
C:\Documents and Settings\USER\Desktop\FOS_Menu\FOS_Menu\build\generated\src\org\apache\jsp\menu_005ftest_jsp.java:60: 'try' without 'catch' or 'finally'
    try {
C:\Documents and Settings\USER\Desktop\FOS_Menu\FOS_Menu\build\generated\src\org\apache\jsp\menu_005ftest_jsp.java:152: 'else' without 'if'
                    } else {
                      ^
C:\Documents and Settings\USER\Desktop\FOS_Menu\FOS_Menu\build\generated\src\org\apache\jsp\menu_005ftest_jsp.java:156: class or interface expected
        }catch (SQLException e){
        ^
C:\Documents and Settings\USER\Desktop\FOS_Menu\FOS_Menu\build\generated\src\org\apache\jsp\menu_005ftest_jsp.java:158: class or interface expected
        }finally{
        ^
C:\Documents and Settings\USER\Desktop\FOS_Menu\FOS_Menu\build\generated\src\org\apache\jsp\menu_005ftest_jsp.java:160: class or interface expected
        ^
C:\Documents and Settings\USER\Desktop\FOS_Menu\FOS_Menu\build\generated\src\org\apache\jsp\menu_005ftest_jsp.java:162: class or interface expected
        ^
C:\Documents and Settings\USER\Desktop\FOS_Menu\FOS_Menu\build\generated\src\org\apache\jsp\menu_005ftest_jsp.java:165: class or interface expected
      out.write("    </body>\n");
      ^
C:\Documents and Settings\USER\Desktop\FOS_Menu\FOS_Menu\build\generated\src\org\apache\jsp\menu_005ftest_jsp.java:166: class or interface expected
      out.write("</html>");
      ^
C:\Documents and Settings\USER\Desktop\FOS_Menu\FOS_Menu\build\generated\src\org\apache\jsp\menu_005ftest_jsp.java:167: class or interface expected
    } catch (Throwable t) {
C:\Documents and Settings\USER\Desktop\FOS_Menu\FOS_Menu\build\generated\src\org\apache\jsp\menu_005ftest_jsp.java:170: class or interface expected
        if (out != null && out.getBufferSize() != 0)
C:\Documents and Settings\USER\Desktop\FOS_Menu\FOS_Menu\build\generated\src\org\apache\jsp\menu_005ftest_jsp.java:172: class or interface expected
        if (_jspx_page_context != null) _jspx_page_context.handlePageException(t);
C:\Documents and Settings\USER\Desktop\FOS_Menu\FOS_Menu\build\generated\src\org\apache\jsp\menu_005ftest_jsp.java:173: class or interface expected
C:\Documents and Settings\USER\Desktop\FOS_Menu\FOS_Menu\build\generated\src\org\apache\jsp\menu_005ftest_jsp.java:176: class or interface expected
16 errorsAnd the code for your reference:
<%@page contentType="text/html"%>
<%@page pageEncoding="UTF-8"%>
<%@page import="FOS.dbconnection.*, FOS.User.*, FOS.Menu.*, javax.servlet.http.*, javax.servlet.jsp.*,javax.servlet.*,
java.sql.*,java.awt.*,java.net.*,java.io.*;"%>
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en-AU">
    <head>
        <title>FOS Menu</title>
        <script type="text/javascript" src="mb.js"></script>
        <link rel="stylesheet" href="mb.css" />
    </head>
    <body onload="mbSet('mb2', 'mbh');">
        <div id="c">
            <div id="eg">
                <ul id="mb2">
                    <%
                    Connection conn = null;
                    Statement stmt;
                    ResultSet rs;
                    String sqlStr;
                    conn = DBConnection.getConnection();
                    try {
                        sqlStr = "SELECT menu_id, menu_name FROM application_mstr WHERE menu_type ='P' AND parent_id='N' ORDER BY module_seq";
                        stmt = conn.createStatement();
                        rs = stmt.executeQuery(sqlStr);
                        while (rs.next()) {
                            String strParentMenuId = rs.getString("menu_id");
                            String strParentMenuName = rs.getString("menu_name");
                    %>
                    <li><a href=""><%= strParentMenuName %></a>
                        <ul>
                            <%
                            getChildren(strParentMenuId);
                            %>
                        </ul>
                    </li>
                    %>
                </ul>
            </div>
        </div>
        <%
                        } catch (SQLException ex) {
                            out.println("<P>" + "Error:");
                            out.println("<PRE>" + ex + "</PRE> \n <P>");
                        } catch (Exception e) {
                            out.println("<P>" + "Error:");
                            out.println("<PRE>" + e + "</PRE> \n <P>");
                        } finally {
                            DBConnection.closeConnection(conn);
        %>
        <%!
        String getChildren(String strMenu_id){
            Connection conn = null;
            PreparedStatement pstmt;
            ResultSet prs;
            String sqlStr;
            try{
                sqlStr = "SELECT menu_id, menu_name, menu_link FROM application_mstr WHERE parent_id=? ORDER BY menu_seq";
                pstmt = DBConnection.getPreparedStatement(conn, sqlStr);
                pstmt.setString(1, strMenu_id);
                prs = pstmt.executeQuery();
                while (prs.next()){
                    String strMenuId = prs.getString("menu_id");
                    String strMenuName = prs.getString("menu_name");
                    String strMenuType = prs.getString("menu_type");
                    String strMenuLink = prs.getString("menu_link");
                    if (strMenuType == "P"){
        %>
        <li><a href='<%=strMenuLink %>'> <%=strMenuName %></a>
        <ul>
            <%
            getChildren(strMenuId);
            %>
        </ul>
        <%
                    } else {
                        out.println("<li><a href=" + strMenuLink + ">" + strMenuName + "</a></li>");
        }catch (SQLException e){
            System.err.println("Error executing stmt :" + e);
        }finally{
            DBConnection.closeConnection(conn);
        return "";
        %>
    </body>
</html>

Error on out.println inside declaration block

I am trying to generate a html page from a method iside the jsp page. When I use out.println inside the declaration block (<%! ---- %>) I am getting following error : "Undefined variable or class name: out".
I have tried using System.out.println, but that sends the output to the consol, and not the html page.
What is the workaround for this ??
Following is the test jsp page to illustrate the problem:
<%@page language="java" %>
<%@page import="wt.doc.*" %>
<%@page import="wt.fc.*" %>
<%@page import="wt.query.*" %>
<jsp:useBean id="wtcontext" class="wt.httpgw.WTContextBean" scope="request"/>
<jsp:setProperty name="wtcontext" property="request" value="<%=request%>"/>
<html>
<body>
<%!
     public void prntest(){
          System.out.println("This will print the message only to console");
          out.println("This does not work");
%>
<h1>This is to test out.println function</h1>
<%
out.println("<br>This out.println statement works as expected<br>");
%>
<br>Now try this<br>
<%prntest();%>
</body>
</html>

Hai ,
Here you are trying to access implict object "out" outside the Scriplets ie in function outside the init/service method .
To get output from prntest() , you have pass a reference of JspWriter out to it .ie Your function should be
<%!
public void prntest(JspWriter out2){
System.out.println("This will print the message only to console");
out2.println("This does not work");
%>
<%prntest(out);%>
This should now work .
rakesh

Redirecting System.err on a mobile phone?

Hi,
Is there a way of redirecting System.err? Unfortunately, System.setErr does not exist in MIDP, so I haven't been able to write my own PrintStream to replace err.
I need to know what the output of Exception.printStackTrace() is at a certain point. There is certainly a way of accessing System.err, otherwise it wouldn't be present in MIDP ... .
Thanks!
Stefan

Hi
J2ME Polish provides a logging framework, which offers different logging levels and the ability to view logging messages on real devices.
Mihai

How to put tab for alignment using out.println?

can anyone tell me how to put something like \t in out.println of JSP/

out.println("<blockquote>your text</blockquote>");

System.out.println() and System.err.println()

Can any one tell me the difference between System.out.println()
and System.err.println() ?

Can any one tell me the difference between
System.out.println() Sends the output to the 'stdout' stream
and System.err.println() ?sends the output to the 'stderr' stream.
http://en.wikipedia.org/wiki/Standard_input

Using System.out.println or System.err.println

Hi All,
I've a Web Dynpro project which uses a simple java helper class.
The java class has 'try catch' statements.
When I'm in 'catch' I want to display an error message on the screen.
I know that System.err.println writes the message in the defaultTrace.trc log file in the server but as a developer I don't always have access to the server.
Is there an option to display the error message on the screen with some kind of response object? (I cannot use wdComponentAPI.getMessageManager.reportSuccess in my helper class)
Thanks,
Omri

Hi Omri,
It's not true that you cannot use the MessageManager in your helper java classes. Here's how you can do it:
1. Create a java class in the src directory of your project and in the same packeage as your project. I think you have already done this. Let's say the class is called HelperClass.
2. Declare a public variable of type com.sap.tc.webdynpro.progmodel.api.IWDMessageManager. Call it say, msgManager. The import will be added automatically.
3. In the wdDoInit() of your WD write something like:
HelperClass helperObj = new HelperClass();
helperObj.msgManager = wdComponentAPI.getMessageManager();
4. Then when you catch the exception in your helper class, do a simple reportException().
Regards,
Satyajit.

Is there a way to force System.out.println to run when called

I working on my first threaded program and having a hard time debugging. I've used System.out.println to let me know what's going on but due (I assume) to the nature of threads the output is not sequential. Is there a way to force println to execute immediatly so that they show up in the order they were called?
Thanks --- Mike

mjs1138 wrote:
endasil, Thanks for the reply. I'm currenlty running the program from within the NetBeans IDE. It is the output displayed by in NetBeans "output" that I'm looking at.
--- MikeI don't use Netbeans, but I would guess that it too pipes Standard Out and Standard Error to the same console. You didn't address my comment. Are you printing to System.err as well? This happens implicitly if you use Exception.printStackTrace(), for example.

Print System.out.println messages into logs of Weblogic Application Server

Hi,
I use Weblogic Application Server 10.3.6 on Windows 7. The Enterprise Application (J2EE) is deployed into the 'AdminServer' of Weblogic. For debugging purpose, I have added a few System.out.println statements.
I am unable to see the print messages on any of log files available in path 'user_projects > domains > base_domain > servers > AdminServer > logs'. However, I can see them on the 'command' prompt which was used to start the server. How can I get them into one of the log files? What am I missing?
I tried reading other threads on the forum and as per them 'System.out.println' gets logged onto *.out logs which I am unable to find. Only base_domain.log, AdminServer.log, access.log are available in the location.
More Specifics:
Configuration on WLS console 'Home > Servers > AdminServer > Logging'
Log file name: logs/AdminServer.log
Min. Severity to log: Notice (tried with Debug as well)
Advanced Options:
Logging Implementation: JDK
Redirect stdout logging enabled: False (tried both options)
Log file Severity Level: Notice (tried with Debug as well)
Standard Out Severity Level: Notice (tried with Debug as well)
Thanks

Paul,
I just found this on google:
'Generally, developers put a lot of System.out.println statements in their code to perform application debugging. Normally, all standard outputs and error outputs are routed to the console where the OC4J server is started. If you want to capture the standard output and error outputs to files for logging/debugging purposes, then you can use the -out and -err options while starting up the Oc4J server to specify which files to use.'.
http://www.onjava.com/pub/a/onjava/2002/01/16/oracle.html?page=2

System.out.println capture to buffer

Hi All,
My application runs other application in back. How can I capture system.out.println() written by another application & display via dialog box.
Like :execl() or execv() function in C runtime library. Where every printf() message printed to passed buffer.
Thank you,
Avin Patel

If i understand your question correctly, you should execute command for you help.html file. The system will run default browser.
such as:
void runBrowser(String file)
{String cmd = null;
     Process p;
          try {
               String os = System.getProperty("os.name");
               if (os != null && os.startsWith("Windows")) {
                    if (os.startsWith("Windows 9") || os.startsWith("Windows Me"))
                    // Windows 9x/Me
                         cmd = "start " + file;
else
                    // Windows NT/2000/XP
                         cmd = "cmd /c start " + file;
p = Runtime.getRuntime().exec(cmd);
catch(IOException x)
// couldn't exec browser
System.err.println("Could not invoke browser, command=" + cmd);
}

Using System.err.println() from within the classes of WAS ?

hi,
I am using admin.jar,a jar file which is being used by Web Application Server in my own class.
I am referencing some of the classes from admin.jar from my class.
I tried to print some trace statements,using System.err.println() from within the classes in admin.jar but they did not reflect in defaulttrace0.trc.
I made these changes in the admin.jar being used by WAS.
I restarted the server and even restarted the machine but without success.
I want to know how to print System.out.println() statements from within the classes in admin.jar.
Also, am i looking for these statements in the right file for eg. defaulttrace0.trc. or is it some other file that i need to look into.
I need urgent help on this.
Reward points assured.
thanks a lot.
Saurav

thanks craig,
ur answer has helped me a lot.but it didnt quite help me.
nevertheless i am trying to set different levels of severity.
Is there anything else that i can do.
Also,i commented out a line of code today in one of the class DataSourceManagerImpl.java in sapj2eenginedeploy.jar
for eg. temp.delete in it deploy method.Buth that line still executed.
I m totally lost as to wht to do.
I m trying to create a datasource from my application in WAS.For that i m using the WAS APIs.But its not working completely.
I am using the above jar and its method createdatasource.
I am callin it from my application's class.
It creates a datasource and i can see it in JDBC Connector list in Visual Administrator.But it appears with red sign meaning its not started.When i start it from the tool then it starts.
But in defaulttrace.trc file it shows an error "FileNotFindException". This happens,and i am very much sure, in the deploy() of DataSourceManagerImpl.java class of sapj2eenginedeploy.jar.
i want to apply println inside this method so i may know where exactly i ma getting the error and get so more info so i may solve my problem.
pls help me.
its really urgent.
thanks again
saurav

System.out.println logged to ?

I am using Oracle 9ias 9.0.3 java edition.
I have deployed a war file successfully using EM.
i HAVE System.out.println statements in my servlets. I was unable to find any documents which tell me where these statements will be logged?
Any one help me.

Go to server properties page of OEM and edit OC4J options under Command Line Options. You will have to specify the OC4J option -out filename to capture the System.out messages. You can also specify the option -err filename to capture all the errors.
check out http://technet.oracle.com/tech/java/oc4j/htdocs/oc4j-logging-debugging-technote.html

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

Where does System.err.println("huh?"); goto?

Hi. Where does the System.err.println("asdfds"); goto for .class files?
When I try this for .jsp files, I get an output line in the console,
expected. :> But when I put it in a class I'm using in that jsp file, I
don't get anything anywhere, or at least no where I found. Can anyone give
me an idea of what I'm doing wrong here? I know I can use the Logger, but
this System.err is just for immediate debugging and I want to pull it out as
soon as I'm done.
Thanks for any input.

I found out what I was doing wrong! :< I was copying the .java file instead
of the .class file. :< Silly. :< Sorry about that.
"PeterH" <!REMOVEBeforeSending![email protected]> wrote in message
news:3c9f48a2$[email protected]..
Hi. Where does the System.err.println("asdfds"); goto for .class files?
When I try this for .jsp files, I get an output line in the console,
expected. :> But when I put it in a class I'm using in that jsp file, I
don't get anything anywhere, or at least no where I found. Can anyonegive
me an idea of what I'm doing wrong here? I know I can use the Logger, but
this System.err is just for immediate debugging and I want to pull it outas
soon as I'm done.
Thanks for any input.

Urgent: Redirecting System.out.println to more than one place

Hi All,
I want to divert all my System.out.println() statements to a Log file as well as on to the screen.
But only one of the 2 options actually works.
So if anyone can suggest me some ways I will appreciate very much.
My code looks something like this:-
if (m_filename != null) {
try {
FileOutputStream fos = new FileOutputStream(m_filename);
PrintStream ps = new PrintStream(fos);
System.setOut(ps);
System.setErr(ps);
//This code Added for Printing Onto Screen But it does not work
Stream ps1 = new PrintStream(System.out);
System.setOut(ps1);
System.setErr(ps1);
} catch (IOException ioe) {
System.out.println("Could not create log file " + m_filename + " because " + ioe);
As far as logging onto file is menat it works when i set it but printing onto screen does not.
How can i achive it
Thanks
Raj

Hi,
You are right but in my current scenario i cannot incorporate this log4j because my application is using some other framework and I am just trying to override this frameworks loggig behaviour so that it logs to both a log file as well as on to the screen.
Here is the code that this framework uses for logging and i am simply overriding it to do the reqd thing but its not working for me:-
* Resets the System's out and err OutputStreams to the Launcher's
* own ThreadedOutputStream, so that output from different threads
* can be tracked efficiently.
protected void setOutputStreams() {
if (scInfo.size() <= 1) {
// don't need Threaded handling with one thread
if (m_filename != null) {
try {
FileOutputStream fos = new FileOutputStream(m_filename);
PrintStream ps = new PrintStream(fos);
System.setOut(ps);
System.setErr(ps);
//Added for Printing Onto Screen
PrintStream ps1 = new PrintStream(System.out);
System.setOut(ps1);
System.setErr(ps1);
} catch (IOException ioe) {
Debug.fatalError("Launcher.setOutputStreams","Could not create log file " + m_filename + " because " + ioe);
else {
Debug.information("Launcher.setOutputStreams","Initializing ThreadedPrintStream");
if (m_filename == null) {
System.setOut(new ThreadedPrintStream(System.out));
System.setErr(new ThreadedPrintStream(System.err));
else {
PrintStream out = new ThreadedPrintStream(m_filename);
System.setOut(out);
System.setErr(out);
//Added for Printing Onto Screen
System.setOut(new ThreadedPrintStream(System.out));
System.setErr(new ThreadedPrintStream(System.err));
Debug.information("Launcher.setOutputStreams","ThreadedPrintStream initialized.");
Thanks
Raj

System.err.println or System.out.println

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