IT Knowledge Sharing | Interview questions

First move tar.gz file into /usr/local/src/ directory and now extract here,   tar    xzvf    apache-tomcat-6.0.35.tar.gz  It will extract apache-tomcat-6.0.35.tar.gz file into directorty apache-tomcat-6.0.35  Rename this directory to tomcat6,   mv apache-tomcat-6.0.35    tomcat6  Now set your environment variable...   cat >> ~/.bashrc  export CATALINA_HOME=/usr/local/src/tomcat6  Save it using ctrl+d and then   source ~/.bashrc Now you can test by starting your tomcat server   sudo $CATALINA_HOME/bin/startup.sh

Use this line in your html code: <a name="fb_share" type="button" share_url="http://knowledge-serve.blogspot.com" ></a>  <a href="https://twitter.com/share" class="twitter-share-button" data-related="jasoncosta" data-lang="en" data-size="medium" data-count="none"></a>       and also include script from Facebook and twitter java script api... <script src="http://static.ak.fbcdn.net/connect.php/js/FB.Share"          type="text/javascript">  </script> <script>!function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs");</script>     

This is the JavaScript code to invite facebook friends (Posting message to their wall) function inviteFBFriend(friend_id,invitation_message){ var opts = {              message : invitation_message,              name : 'Hello User',              description : 'Facebook is great!',              picture : 'http://www.knowledgeserve.in/images/knowledgeServeLogo.jpg '     }; FB.api('/'+friend_id+'/feed', 'post', opts , function(response) {        if (!response || response.error) {         alert('Error occured');                    } else {            alert('Post ID: ' + response.id);        }      }); }

Add this coe to body element of your html file..... <div id="findAllFriends">     <div id="fb-root"></div>          <div class="fb_login_user_status">         <a class="fb_button fb_button_medium">             <span id="fb-auth" class="fb_button_text">Log In with Facebook</span>         </a>      </div>      <div class="fbUser" id="user-info"></div     <div id="friendslistFB" >        <table id="fbFriends" width="100%" border="0" >        </table>        </div>    </div> /**** Java Script code ********/ var facebookAppId=' your facebook app id '; window.fbAsyncInit = function() {   FB.init({ appId: facebookAppId,     status: true,  ...

Access value form <s:iterator> into <s:if> (ognl with <s:if> and <s:iterator>) For example: Suppose loadUserList is the itertaor(containing UserName and Address ) to be iterate on jsp, <s:if test="loadUserList != null && loadUserList.isEmpty()">   <s:iterator value="loadUserWalksResults" status="rowStatus">                   UserName :<s:property escape="false" value="userName" /> Address: <s:property escape="false" value="address" /> <s:if test='userName.equals("Admin")'>This is admin User</s:if> <s:else>This is not an admin user!</s:else>   </s:iterator> </s:if>

The <s:iterator> tag is widely used on UI (jsp)  to iterate some collection returned by any action. <table class="facebookFriendList">    <tr class="even">        <td><b>UserName</b></td>        <td><b>ProfileImage</b></td>     </tr>    <s:iterator value="facebookFriendList" status="rowStatus">      <tr class="<s:if test="rowStatus.odd == true ">odd</s:if><s:else>even</s:else>">          <td><s:property value="userName" /></td>          <td><s:property value="profileImageURL" /></td>      </tr>      </s:iterator> </table> We use the iterator tag to iterator over the collections. See OGNL expression #statusName. Properties of the IteratorStatu...

Getting real client ip-address using java (if Apache redirection is used...) -------------------------------------------------------------------------- You can use ,     String ipAddress = request.getHeader("X-Forwarded-For");  if you have configured Apache redirection. ------------------------------------------------------------------------- If you will use      request.getRemoteAddr(), it may return 127.0.0.1 if apache redirection has been configured at your deployment server.