Zeeshan Ahmed Memon Blog: 2016

Tuesday, July 26, 2016

Could not get lock /var/lib/dpkg/lock

Today, I tried to install Git on my Ubuntu machine and during that I received following exception related to locking. In my this post, I have shared all commands and error messages with you.

Command
sudo apt-get install git

Error Message
E: Could not get lock /var/lib/dpkg/lock - open (11: Resource temporarily unavailable)
E: Unable to lock the administration directory (/var/lib/dpkg/), is another process using it?

After searching above message, I found a command

sudo lsof /var/lib/dpkg/lock

after pressing ENTER, it might asked you for password. Type the password and in result you might get following output

lsof: WARNING: can't stat() fuse.gvfsd-fuse file system /run/user/1000/gvfs

Output information may be incomplete.

COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME

unattende 1468 root 5uW REG 8,1 0 154817 /var/lib/dpkg/lock

Type following command to kill the session with provided PID by your system. In my case PID # was 1468. I use following command to kill this process id.

sudo kill 1468

After execution of above statement, now I was able to download GIT by using following command again which I executed in start.

sudo apt-get install git

In case if this article helps you then please leave a comment to increase its credibility.

Thanks.

Sunday, July 24, 2016

NodeJS Series: Calling Sleep Method.

Dear Friends,

This is my first article about NodeJS, I am currently exploring it and problems which I found during my learning sessions, I will share it to you with my blog posts.

Today while writing some code, I come across the need of sleep functionality between two transactions. While doing google, I found "sleep" library which provide required functionality.

Calling of sleep method is simple e.g.,

sleep.sleep(1) // time will be defined in seconds

But before that you need sleep library / package. To download it, use following npm command

npm install sleep

After successful installation, write following code to test this functionality.

var sleep = require('sleep');

function callLoops()
{
for(var a=1;a<10;a++)
{
console.log('%d',a);
sleep.sleep(1); //times in seconds.
}
}

callLoops();

and save this code in myExample.js file.

Execute the file with following command

node myExample.js

Congratulations...... You have achieved the goal.

That's all for now folks..... If this post help you then please increase its credibility by posting your comments.

Thanks.

Monday, March 14, 2016

HOW TO USE SPRINGFORM:ERROR TAG

To use Spring Form Error Tag, you have to follow following steps.

Your JSP Page should look like this:

<%@page contentType="text/html" pageEncoding="UTF-8"%>
<%@taglib prefix="sf" uri="http://www.springframework.org/tags/form" %>

<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<title>About Us Page</title>
</head>
<body>
<sf:form method="POST" action ="/SpringBasics/redirect.aspx" modelAttribute="basicClass">
FirstName: <sf:input path="firstName" />
<sf:errors path="firstName" />
<br/>
<input type="submit" value="Redirect Page" />
</sf:form>
</body>
</html>

java.lang.IllegalStateException: Neither BindingResult nor plain target object for bean name 'xxx' available as request attribute

While trying to use Spring MVC form Tags, I come across following exception

java.lang.IllegalStateException: Neither BindingResult nor plain target object for bean name 'userInput' available as request attribute

Below is my JSP Code with Spring Tags

<%@page contentType="text/html" pageEncoding="UTF-8" session="false" %>
<%@taglib uri="http://www.springframework.org/tags" prefix="st"%>
<%@taglib uri="http://www.springframework.org/tags/form" prefix="sf"%>
<!DOCTYPE html>
<html>
    
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title>About Us Page</title>        
        <st:url var="bootstrapp_theme" value="/resources/css/bootstrap-theme.css" />
        <st:url var="bootstrapp_css" value="/resources/css/bootstrap.css" />
        <st:url var="jquery" value="/resources/js/jquery-2.2.0.js" />
        <st:url var="bootstrapp_js" value="/resources/js/bootstrap.js" />
        <link href="${bootstrapp_theme}" rel="stylesheet" />
        <link href="${bootstrapp_css}" rel="stylesheet" />        
        <script src="${jquery}" ></script>
        <script src="${bootstrapp_js}" ></script>
        
        
    <body>
        <h1 class="text-center">ABC CORPORATION</h1>
        
        <sf:form method="POST" action ="/SpringBasics/redirect">
            
            <table>
                <tr>
                
                    <td>Login ID: &nbsp;&nbsp;<input type="text" name="userName" />
                       <br> Email: &nbsp;&nbsp;<sf:input type="email" path="email" />
                       <br> My Label: &nbsp;&nbsp;<sf:label id="lbl1" path="myLabel"   />
                         
                    </td>
                </tr>
                <tr>
                    
                    <td>Password:&nbsp;&nbsp;<input type="number"  name="extension" /></td>
                </tr>
            </table>


            <input type="submit" value="Redirect Page" />
        </sf:form>
    </body>
</html>

To resolve it I created a properties class which is defined below

package springbasics;

/**

*

* @author Zeeshan

*/

public class userInput {

protected String _email;

protected String _myLabel;

public String getMyLabel() {

return _myLabel;

}

public void setMyLabel(String _myLabel) {

this._myLabel = _myLabel;

}

public String getEmail() {

return _email;

}

public void setEmail(String _email) {

this._email = _email;

}

}

and change my JSP Code from

<sf:form method="POST" action ="/SpringBasics/redirect">

<sf:form method="POST" action ="/SpringBasics/redirect" modelAttribute="userInput" >

Also change my controller class parameter From

@RequestMapping(value = "/", method = GET)

public String aboutUs() {

return "aboutus";

}

@RequestMapping(value = "/", method = GET)

public String aboutUs(userInput obj) {

return "aboutus";

}

This resolve the above error message.

If suggested solution help you in solving your issue then please comment to increase its credibility.

Thanks.

Thursday, January 28, 2016

SCRIPT AUTOMATICALLY EXECUTE ON CONSOLE OPENING

Dear Linux Lovers,

If you want to load a shell script automatically whenever console is opened by user then right it in " .bashrc " file. The file exists in user home directory. To edit .bashrc simply write

vi .bashrc /*To open in VI*/

or any other editor which you love.

Enjoy Linux World.

No Launcher Load in Ubuntu

Sometimes UBUNTU does not show launcher due to some problem and in that case we have to re-install the O/S again. I come across this problem several times but today I did some research and found this easiest solution which work for me and I hope that It will work for you as well.

Follow below steps to get your UBUNTU launcher back:

1) Press CTRL+ALT+DTL in vm ware (3 Buttons combine) to open your processes window inside Virtual Machine.

2) Go to 3rd Tab (Disk) and double click on /dev/sda1. This will open your Files Explorer.

3) Now press CTRL+F for searching and find TERMINAL.

4) Open TERMINAL.

5) Write " sudo apt-get update "

6) Write " sudo apt-get install unity " to install Unity which will display you LAUNCHER.

7) Write " sudo reboot " to reboot your Virtual Machine.

After your computer / Virtual Machine is reboot, you can see your LAUNCHER back.

Above steps resolve my problem and if does the same in your case then please comment so the reliability of the post will increase.

Thanks.

Sunday, January 17, 2016

Unable to run mksdcard SDK tool.

During configuration of Android IntelliJ on UBUNTU, you might come across subjected message. Following command will help you in resolving this issue.

sudo apt-get install lib32z1 lib32ncurses5 lib32bz2-1.0 lib32stdc++6

HOW TO REMOVE ALL JDK FROM UBUNTU

Following command will remove all JDK versions from your computer in UBUNTU

sudo apt-get purge openjdk-*

In case if above code help you then please leave a comment for its authenticity to others.

Zeeshan Ahmed Memon Blog