install apache benchmarking tool – ‘ab’

On WINDOWS machine :

Download httpd-****-x86 from http://httpd.apache.org/download.cgi

After going through the installation process –> Go to the directory where its installed

similar to C:\httpd-2.4.12-x86\Apache24\bin in my case, add this to system ENV Variable

 

On UNIX machine :

did not work –>> sudo yum install httpd-tools

Below long procedure worked, and it also needed to switch to root user and running it, running command with sudo did not work

You will need to install apr-utils and yum-utils first.

yum -y install apr-util
yum -y install yum-utils

 

extract Apache Benchmark from httpd-tools. And here is how.

mkdir ~/httpd-tools

cd ~/httpd-tools

yumdownloader httpd-tools

 

Now extract ab (Apache Benchmark) and move it to  /usr/bin  folder

rpm2cpio httpd-tools-2.2.24-1.29.amzn1.x86_64.rpm | cpio -idmv

mv usr/bin/ab /usr/bin/ab

cd ~

rm -rf ~/httpd-tools

 

 

sample command to test with –

ab -ki -n 500000 -c 200 http://rusticode.com/2013/04/07/lannn-installing-apache-benchmark-on-centos-ec2-linux-ami-with-nginx/

-n    specifies the number of requests,

-c    number of concurrent connections,

-k    stands for HTTP Keep-Alive,  

-t    maximum time of awaiting for response from connection

install apache benchmarking tool – ‘ab’

sudo yum install httpd-tools

 

sample command to test with –

ab -ki -n 500000 -c 200 http://serverfault.com/questions/240496/is-there-a-way-to-install-apache-bench-ab-without-installing-apache

Setup up ssh to login without entering password

Considering situation where we need to connect from Server A to Server B

• On Server A, run the below command to generate the public key

  ssh-keygen -t rsa

  Note: If you don’t have ssh-keygen command recognized in your system, install Git – which will provide required file for running ssh-keygen command.

  After installing Git, add this/similar path to your system environment variable C:\Program Files (x86)\Git\bin\ssh-keygen.exe

  This command should generate id_rsa.pub file in your <homedir>/.ssh/ directory

• On Server B

  create a folder in the <homedir> with name .ssh

  Copy the id_rsa.pub file from Server A, into this .ssh directory.

  Append the contents of id_rsa.pub file to authorized_keys file inside the .ssh directory on Server B.  If one authorized_keys file does not exist – create it.

That’s it! now we should be able to login without having to enter password every single time.

Loading jndi.properties file from specific path

         Context context = null;
         try {
                File configFile = new File(“<provide absolute path to your my.jndi.properties file>“);
                Properties prop = new Properties();
                FileInputStream istream = new FileInputStream(configFile);
                prop.load(istream);
                context = new InitialContext(prop);
            } catch (NamingException e1) {
                // TODO Auto-generated catch block
                e1.printStackTrace();
            } catch (FileNotFoundException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

Java Single Jar file with multiple main method classes

/**
* Sample launcher
*/
public class Launcher {

    public static void main(String[] args) throws Exception {
        if (args != null && args.length > 0) {
            String option = args[0];
            String[] args2 = new String[0];

            if (args.length > 1) {
                args2 = new String[args.length – 1];
                System.arraycopy(args, 1, args2, 0, args2.length);
            }

            if (option.equals(“JbossJavaTCPSender”))
                new JbossJavaTCPSender().exec(args2);
            else if (option.equals(“JbossJavaTCPReceiver”))
                new JbossJavaTCPReceiver().exec(args2);
            else
                System.out.println(“Connot find such class to execute having name [“
                        + option+”]”);
        } else
            {
            System.out.println(“Usage : Provide ClassName as an argument to execute.”);
            System.out.println(“\t[java -jar JbossJavaTCPExample.jar JbossJavaTCPSender]”);
            System.out.println(“\t[java -jar JbossJavaTCPExample.jar JbossJavaTCPReceiver]”);
            }
    }
}

windows task scheduler

Control Panel\All Control Panel Items\Administrative Tools –> Task scheduler –> create basic task

java specifying jar file while running program from command line

Solution:

Spent one whole day to figure out semicolon(;) in windows is equivalent to specifying colon(:) on unix platform.

If all of the jars are placed into a folder called ‘jars’ in the current directory.

on Windows –> java -cp .;jars/* AbsoluteClassname arguments

Unix –> java -cp .:jars/* AbsoluteClassname arguments

 

Problem:

Exception in thread “main” java.lang.NoClassDefFoundError:

windows sidebar

Best Must have Utilities / Tools for windows!!

In Process, to be updated soon…

Java Collections contains Substring

By default list.contains(“String”) check for complete match in each line, so searching for list.contain(“ing”) would return false.

This is what I did for solution:

Convert list collection to String and then search in this complete Collection String contains our substring “ing”

Example: sample code below list elements in list1 that are not present in list2.  Also while comparing it compares only for first 7 characters

String x = list2.toString();
for(String a:list1){
   String b = a.substring(0,7);
   if(!x.contains(b))
       System.out.println(a);
}