System Programming





Kernel and system programming is the process of creating the software necessary for a computer or device to function and operate other programs. Some operating systems (such as Microsoft Windows) are proprietary, but others, such as the various Linux distributions, are open source.

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when i  try to missing junit to build path showing 2 options. i wonder why it shows same option 2 times. please advise
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while opening team explored in eclipse mars getting below error

Plug-in "" was unable to instantiate class "".

how to resolve this.

Please advise

i wrote my web application with web.xml as below

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi=""
	id="WebApp_ID" version="3.1">
	<!-- 	<form-login-config>
		</form-login-config> -->

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i added role and username and password to tomcat-users.xml as below

<?xml version="1.0" encoding="UTF-8"?>
  Licensed to the Apache Software Foundation (ASF) under one or more
  contributor license agreements.  See the NOTICE file distributed with
  this work for additional information regarding copyright ownership.
  The ASF licenses this file to You under the Apache License, Version 2.0
  (the "License"); you may not use this file except in compliance with
  the License.  You may obtain a copy of the 

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I got below error
The superclass "javax.servlet.http.HttpServlet" was not found on the Java Build Path
i checked below which has tomcat 8 already.

Project → Properties → Target Runtimes → *Apache Tomcat worked for me. There is no Target Runtimes under Facets (I'm on Eclipse v4.4 (Luna)).

i just has to remove and add again to  resolve this error.

i wonder why i have to remove and re add to resolve. this does not make sense to me. please advise

I am trying below example

i fired 100 messages as decribed in tutorial and exepcted them to be consumed with message on console.

Intead i am gettign below error

SEVERE: Could not refresh JMS Connection for destination 'jmsReceiveJndi' - retrying using FixedBackOff{interval=5000, currentAttempts=21, maxAttempts=unlimited}. Cause: Cannot send, channel has already failed: tcp://

under meta-inf context.xml is as below

<?xml version="1.0" encoding="UTF-8"?>

               Active MQ Connection Factory manages pooled connections
               to the ActiveMQ broker. Tomcat will connect with the
               broker using a TCP connection on port 61616 - this is the
               default port for ActiveMQ
   <Resource name="jms/mqConnectionFactory"
                     description="JMS Connection Factory"
               brokerURL="tcp://localhost:8161" />

               This is a reference to the first Queue we defined
               earlier in the ActiveMQ admin console
   <Resource name="jms/testQueueOne"

               This is a reference to …
while trying below example

i did all stepas given

when i execute i do not see 3 mesages there

Example Execution:

Start ActiveMQ and login as admin/admin and click on “Queues” tab.
Start Tomcat and deploy the application. You should see three listeners listening to “firstQueue”.

what is difference between

which one i have to use.

my active mq running on my own windows laptop locally?
when to use http wen to use ftp?
when to use local host when to use ip like number 127.x.y.z...
please advise

I am looking for good sample example on below area
JMS API Durable subscriber example
can you please point me to some end to end example on this using active mq.

Please advise

can i open two instances of eclipse mars both pointing to same tomcat 8 pointing ?
is that is ok or do i get any error like port conflict or something else?
please advise

within eclipse i have tomcat 8 running. I want to know what location that tomcat running from on my local windows laptop C drive as i happened to have many tomcats in my c drive under different directories
hi am geting this error after running the antivirus am not even able to start my pc in safe mode mode am in window 10 The application was unable to start correctly 0xc0000005 am in window 10
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i am working on below example

i wrote my publisher as below

package pubSub;    
import javax.naming.Context;
import javax.naming.InitialContext;                                                                          
import javax.jms.Topic;
import javax.jms.Session;
import javax.jms.TextMessage;
import javax.jms.TopicPublisher;

import java.util.Properties;

import javax.jms.DeliveryMode;
import javax.jms.TopicSession;
import javax.jms.TopicConnection;
import javax.jms.TopicConnectionFactory;
public class Publisher
    public static void main(String[] args) throws Exception
    	// Obtain a JNDI connection
    	Properties env = new Properties();
    	env.put(Context.PROVIDER_URL, “http://localhost:8161”);
    	//env.put(Context.SECURITY_PRINCIPAL, “weblogic”);
    	//env.put(Context.SECURITY_CREDENTIALS, “weblogic”);

    	InitialContext ctx = new InitialContext(env);
       // get the initial context
       InitialContext ctx = new InitialContext();
       // lookup the topic object
       Topic topic = (Topic) ctx.lookup("topic/topic0");

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my project has different environment related property files like int, sT, PT, Prod etc to call various service (like email service, validate service etc)

using maven build command from command prompt or eclipse how to pass environment like integraion for example

pom.xml has filter entry i heard which does check like this
any good links, examples on this
please advise
I'm using currently the project
to check if a web portal, for example, works fine with EOT, WOFF and TTF to displaying different icons.

It looks like fonts with the Content-Type application/ or application/font-woff could not be used with IWebBrowser2.
In the webtraffic i could see, that the app could download the fonts, but after the download i received the error E_ABORT in the IHttpNegotiate::OnResponse handler.

The web pages works in IE, but when we disable font download in the security settings we get the same 'problem' with the IE.

I tried to enable the font download in function IInternetSecurityManager::ProcessUrlAction
(URLACTION_HTML_FONT_DOWNLOAD) without a positive result.

What i'm doing wrong?
Hi Experts

Could you explain how was the mainframes programs strategy to deal with low hardware resouces, decades ago, when developing banking applications like checking accounts, legal accounting, etc. a typical area with huge amount of data.

I guess there was one computer designated to treat each big agency data and then one other only to sumarize. Am I right?
Could you give details, mainly if you lived this situation?

Thanks in advance!

I have configured eclipse with tomcat 8

i modified my tomcat-users.xml by doing cntr+shift+R and searching on tomcat-users.xml

i added below entry as i am getting tomcat username and password screen when i run rest web services 139 query parameter example from annotation
when i give tomcat , tomcat getting anauthorized error

  <user name="admin" password="admin" roles="admin-gui,manager-gui" />

after addin above when i restart getting below
Could not load the Tomcat server configuration at /Servers/Tomcat v8.0 Server at localhost-config. The configuration may be corrupt or incomplete

How to solve:

Close Eclipse
Copy all files from TOMCAT_7_HOME/conf to WORKSPACE_FOLDER/Servers/Tomcat v7.0 Server at localhost-config
Start Eclipse
Expand the Servers project, click on the Tomcat 7 project and hit F5
Start Tomcat from Eclipse

to folow above steps how to where is my tomcat conf directory or where the tomcat directory is ?
is there is a way in eclipse you can see properties etc to find it?
how to know my server is tomcat 8 or tomcat 8.5 etc

how to solve this error
please advise
How to resolve this?


I am reading about nested loop here

for (int i = 1; i <= 5; i++) {
 for (int j = 1; j <= i; j++) {

Think of a nested loop as a race track within a race track. When you begin each lap on the main oval, you veer into another track inside the original (the nested track/loop). You may go around any number of times within the smaller track before looping around the main one. Then it starts over again until you've done the required number of laps on the main track. In all, you may go around a thousand times, or many more!

what it means by race track within a race track not able to visualize this image or picture
what it means by each lap on main oval and veer to another track inside original track??

please advise
 let us say i give some random number like 81349 on console i should see output as by ascending order of each digit in each line how to achieve that as well

    3 3
   4 4 4
 8 8 8 8
9 9 9 9 9

how to to achive this
please advise

i am going through below link

eclipse what is difference between control1 and control 2 when to use which one?

please advise

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I just bought a golf cart  that has a pro link monitor. Is it possible to reprogram for the gps when the golf course doesn't have the system. I basically just want the gps.
I am curious about finding the cost to a big bank to process something like a bank transfer from one account to another...

I am thinking about my bank, where I have two accounts, where I may move a few hundred dollars from one account to another.

Is the cost less than a penny for such a transaction for a website or an iPhone app to make such a transfer? I assume there are overhead costs where auditors review blocks of transactions, but I am not asking about that. Just the marginal cost for a hosted and highly secure website to process a transaction.

Does anyone have an idea about this?
Hi Experts,

I have written a program that reads the network interfaces to retrieve the MAC addresses for the network cards/interfaces in the computer.

The program sets up a http server to run locally on every machine, listening on a port for the API calls. For each request I'm starting a new thread, and in that thread I make a call to retrieve this information.

However, sometimes the program crashes entirely (not just the thread serving the request, but the entire program itself), without any logs or exceptions.

I'm not too sure what the cause is, but I suspect it may have to do with the NetworkInterface.GetAllNetworkInterfaces() call, as my logs stop there everytime it randomly crashes. Usually, even if a COMException occurs (due to some native DLL I'm using), the server would still be up and running, but in this case, the server closes entirely.

I have also tried this on my colleague's computer; it seems to be fine for him, but mine crashes randomly, perhaps once every 100 requests?

My question is, is there a known issue with the NetworkInterface.GetAllNetworkInterfaces() call? If not, is there a way for me to properly debug and find the cause of this issue?

Best Regards,
i need ideas (or a script) how to search all MAC Addresses of a windows system and pass these as parameter to an external program...with PERL.

script should do the following:
1. get all MAC-Adresses (LAN1, LAN2, WLAN,...)

2. start external programm and pass every MAC (one after another) ... possible within a loop
extProg.exe AA-AA-AA-AA-AA-AA
extProg.exe BB-BB-BB-BB-BB-BB
extProg.exe CC-CC-CC-CC-CC-CC-CC
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In Microsoft Access, I have a form which currently opens up a number of pdf's (currently in Acrobat Reader). My goal is to open up the same number of pdf's in IE, but have them grouped by color. The way the sort of the list is made, the first tab in a group is an image of a purchase order, the following tabs are pdf's of vendor invoices. Often times there is a one to one relationship between purchase order and invoice, however on a fairly regular basis there may be more than one invoice to the purchase order. I would like to make it clear to the user by colored tabs, the relationship of Purchase Orders to Invoices.

The selection criteria and Path has been commented out. Printing works fine, but is also commented out at the moment.

Private Sub Command0_Click()
Dim db As Database
Dim rst As DAO.Recordset
Dim StrSQL As String
Dim PathName As String
Dim PO As String

Set db = CurrentDb()


Set rst = db.OpenRecordset(kaySQL, dbOpenDynaset, dbSeeChanges)
Do Until rst.EOF
  PathName = "SomePath" & rst("Image-no") & ".PDF"

 CreateObject("Shell.Application").Namespace(0).ParseName(PathName).InvokeVerb ("Open")
 'CreateObject("Shell.Application").Namespace(0).ParseName(PathName).InvokeVerb ("Print")


End Sub

System Programming





Kernel and system programming is the process of creating the software necessary for a computer or device to function and operate other programs. Some operating systems (such as Microsoft Windows) are proprietary, but others, such as the various Linux distributions, are open source.