11. March 2012

29.3. 2012 – Slovakia AUG – Bratislava – Invitation

Adobe User Group Slovakia is organizing another event for fans and friends of Adobe technologies.

Where: Galvaniho 17/C, Bratislava, Slovakia – IBL Software Engineering office

When: 29.3. 2012 – 17:00 – 20:00

You can find more details about Adobe User Group Slovakia at: slovakia.groups.adobe.com

Feel free to join this event. 🙂

10. March 2012

Tomcat 7 listen on port 80 – Linux Debian

The default installation of Tomcat 7 for Linux Debian is listening on port 8080.

When you want to change the port to 80 then you have several options.

You can use iptables and redirect communication from port 8080 to port 80.

iptables -t nat -P PREROUTING -p tcp -m tcp --dport 80 -j REDIRECT --to-port 8080

The more straight forward approach is to bind Tomcat directly to port 80. First of all change port 8080 to 80 in file /etc/tomcat7/server.xml.

You’ll see error messages in /var/log/tomcat7/catalina.out when you try to restart Tomcat:

SEVERE: Failed to initialize connector [Connector[HTTP/1.1-80]]
org.apache.catalina.LifecycleException: Failed to initialize component [Connector[HTTP/1.1-80]]
Caused by: java.net.BindException: Permission denied

The problem is that default installation of Tomcat 7 for Linux Debian allows to bind only ports higher than 1023. You need to allow binding to privileged ports.

Open file /etc/defaults/tomcat7 and change option from:




Restart Tomcat and it will listen on port 80.

7. March 2012

Web stress test by Apache Benchmarking Tool

Sometimes you need to identify bottleneck of web application.

You can use Selenium to record and repeat the same steps over and over.

Another solution is to use Apache Benchmarking Tool.

E.g. You need to send 1000 requests in 10 concurrent threads to localhost:

ab -c 10 -n 1000 http://localhost/

For Debian users: you can find this mighty command in apache2-utils package.

Sample result:

Server Software:        Apache-Coyote/1.1
Server Hostname:        localhost
Server Port:            80

Document Path:          /
Document Length:        405 bytes

Concurrency Level:      10
Time taken for tests:   0.524 seconds
Complete requests:      1000
Failed requests:        0
Write errors:           0
Total transferred:      650000 bytes
HTML transferred:       405000 bytes
Requests per second:    1907.13 [#/sec] (mean)
Time per request:       5.243 [ms] (mean)
Time per request:       0.524 [ms] (mean, across all concurrent requests)
Transfer rate:          1210.58 [Kbytes/sec] received

Connection Times (ms)
              min  mean[+/-sd] median   max
Connect:        0    2   0.5      2       4
Processing:     0    3   0.5      3       4
Waiting:        0    2   0.7      2       4
Total:          2    5   0.3      5       8

3. March 2012

Video – YSoft SafeQ 4 Launch Event in Prague

Check out cool videos from SafeQ 4 Launch Event in Prague.


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