Java 4 Ever

This is a really funny video about Java!

Sonar (Code Quality Management System)

Sonar is an open system to manage code quality. It monitors the 7 axes of code quality:

• Architecture & Design
  
• Comments
  
• Duplications
  
• Coding rules
  
• Unit tests
  
• Potential bugs
  
• Complexity
  

More info: http://www.sonarsource.org/

Setting response MIME-type in Java ServerFaces

To set the MIME-type in JSF, use the following code in your JSP-page:

<% response.setContentType("text/plain"); %>

In this example, the MIME-type is set to plain text. The browser will treat the page as plain text and will not render the page as a HTML-page.

Here is a list of common MIME-types.

Fixing ^M characters in VI

The new line in UNIX-like OS is represented differently than in Windows OS. When a Windows file is viewed in the VI editor, you can see ^M where the line ends. You can remove the ^M character by using the following VI regular expression command:

:%s/^V^M//g

The ^-sign means holding the CTRL-key while pressing the next character.

Getting client information in Java ServerFaces

I always log client information in JSF applications in debug mode. I use the following code in a managed bean to retrieve the IP-address, hostname and HTTP-headers from the browser.

// Get the request-object.
HttpServletRequest request = (HttpServletRequest)
(FacesContext.getCurrentInstance().
getExternalContext().getRequest());

// Get the header attributes. Use them to retrieve the actual
// values.
request.getHeaderNames();

// Get the IP-address of the client.
request.getRemoteAddr();

// Get the hostname of the client.
request.getRemoteHost();