I love Jetty for its low maintenance cost. It&#39;s just unpack and it&#39;s ready to roll. Tomcat is a bit high maintenance, requires more configuration and it&#39;s heavier. Besides, Jetty&#39;s continuations are very cool.

EDIT: In 2013, there are reports that Tomcat has gotten easier. See comments. I haven&#39;t verified that.

I think tomcat is more disscussed and supported by application, Jetty is portable and can be embedded in an application. and Jetty has good continuations.

I like how Jetty can be embedded in an application so that it doesn&#39;t need to run in a web container (Hudson and Nexus are two apps that can run in this mode). Can Tomcat do this?

What would be a set of nifty preprocessor hacks (ANSI C89/ISO C90 compatible) which enable some kind of ugly (but usable) object-orientation in C?

I am familiar with a few different object-oriented languages, so please don&#39;t respond with answers like &quot;Learn C++!&quot;. I have read &quot;[Object-Oriented Programming With ANSI C][1]&quot; (beware: **PDF format**) and several other interesting solutions, but I&#39;m mostly interested in yours :-)!

----------

See also *[Can you write object oriented code in C?][2]*

 [1]: http://www.planetpdf.com/codecuts/pdfs/ooc.pdf &quot;Object-Oriented Programming With ANSI C&quot;
 [2]: https://stackoverflow.com/questions/351733 &quot;Can you write object oriented code in C?&quot;


Object-orientation in C

I know it is a good practice to declare virtual destructors for base classes in C++, but is it always important to declare `virtual` destructors even for abstract classes that function as interfaces? Please provide some reasons and examples why.

Why should I declare a virtual destructor for an abstract class in C++?

I&#39;m wondering about the downsides of each servers in respect to a production environment. Did anyone have big problems with one of the features? Performance, etc. I also quickly took a look at the new Glassfish, does it match up the simple servlet containers (it seems to have a good management interface at least)?

Tomcat VS Jetty

<p>I'm wondering about the downsides of each servers in respect to a production environment. Did anyone have big problems with one of the features? Performance, etc. I also quickly took a look at the new Glassfish, does it match up the simple servlet containers (it seems to have a good management interface at least)?</p>


I am looking to use Java to get the MD5 checksum of a file.  I was really surprised but I haven&#39;t been able to find anything that shows how to get the MD5 checksum of a file.

How is it done?

Getting a File&#39;s MD5 Checksum in Java

There is two available Eclipse plugins for Maven :

  - [Eclipse IAM][1] (old name is Q4E)
  - [m2eclipse][2]

m2eclipse seems to be the oldest but the more robust. Is there any key differences between the two ?

Which one should be chosen for a project starting today and why ?

**UPDATE:** m2eclipse is moving to eclipse.org and will be included in the Indigo release train (Eclipse 3.7). See [m2e at Eclipse: What will this mean for you?][3] and [m2eclipse is moving to eclipse.org!][4]. The accepted answer is thus even more correct.

  [1]: http://www.eclipse.org/proposals/iam/
  [2]: http://m2eclipse.codehaus.org/
  [3]: http://www.sonatype.com/people/2010/12/m2e-at-eclipse-what-will-this-mean-for-you/
  [4]: http://www.eclipse.org/m2e/

Which is the best Maven Eclipse plugin?

I have a groovy script that needs a library in a jar. How do I add that to the classpath? I want the script to be executable so I&#39;m using `#!/usr/bin/env groovy` at the top of my script. 

How do I include jars in a groovy script?

I am having trouble deleting orphan nodes using JPA with the following mapping

    @OneToMany (cascade = CascadeType.ALL, fetch = FetchType.EAGER, mappedBy = &quot;owner&quot;)
    private List&lt;Bikes&gt; bikes;

I am having the issue of the orphaned roles hanging around the database.

I can use the annotation `org.hibernate.annotations.Cascade` Hibernate specific tag but obviously I don&#39;t want to tie my solution into a Hibernate implementation.


**EDIT**: It seems JPA 2.0 will include support for this.

JPA CascadeType.ALL does not delete orphans

I&#39;m having some trouble navigating Java&#39;s rule for inferring generic type parameters. Consider the following class, which has an optional list parameter: 

    import java.util.Collections;
    import java.util.List;
    
    public class Person {
      private String name;
      private List&lt;String&gt; nicknames;
      
      public Person(String name) {
        this(name, Collections.emptyList());
      }
      
      public Person(String name, List&lt;String&gt; nicknames) {
        this.name = name;
        this.nicknames = nicknames;
      }
    }

My Java compiler gives the following error:

    Person.java:9: The constructor Person(String, List&lt;Object&gt;) is undefined

But `Collections.emptyList()` returns type `&lt;T&gt; List&lt;T&gt;`, not `List&lt;Object&gt;`. Adding a cast doesn&#39;t help

    public Person(String name) {
      this(name,(List&lt;String&gt;)Collections.emptyList());
    }

yields

    Person.java:9: inconvertible types

Using `EMPTY_LIST` instead of `emptyList()` 

    public Person(String name) {
      this(name, Collections.EMPTY_LIST);
    }

yields 

    Person.java:9: warning: [unchecked] unchecked conversion

Whereas the following change makes the error go away:

    public Person(String name) {
      this.name = name;
      this.nicknames = Collections.emptyList();
    }

Can anyone explain what type-checking rule I&#39;m running up against here, and the best way to work around it? In this example, the final code example is satisfactory, but with larger classes, I&#39;d like to be able to write methods following this &quot;optional parameter&quot; pattern without duplicating code.

For extra credit: when is it appropriate to use `EMPTY_LIST` as opposed to `emptyList()`?

Collections.emptyList() returns a List&lt;Object&gt;?

I understand that I can specify system properties to Tomcat by passing arguments with the -D parameter, for example &quot;**-Dmy.prop=value**&quot;.

I am wondering if there is a cleaner way of doing this by specifying the property values in the context.xml file or some other tomcat configuration file. I would like to do this because, first, it is easier to keep track of my properties, and second, I have multiple contexts running and I don&#39;t know how I would specify context-specific properties through the -D parameter.

I am using Tomcat version 5.5.


How can I specify system properties in Tomcat configuration on startup?

How can i use Tomcat to serve image files from a public folder outside webapps? I dont want to use a 2nd Apache fileserver on a different port since the image files are part of the same app. And i dont want to create a symlink to the public folder inside webapps since my app is deployed as a war file....Is there a simpler solution similar to using default servlet for static content inside webapps, for static content outside outside webapps

How to config Tomcat to serve images from an external folder outside webapps?

I&#39;m currently running my webapps on Tomcat 6 in production, and would like to evaluate running Tomcat in embedded mode.

Is there a good tutorial or other resource besides what&#39;s in the [api documentation][1]?


  [1]: http://tomcat.apache.org/tomcat-6.0-doc/api/org/apache/catalina/startup/Embedded.html

How to embed Tomcat 6?

Is there an easy way to specify an alternate port for Tomcat in the pom or on the commandline. I&#39;d like to have several projects running on the same machine. 

Alternate port for Tomcat (not 8080) when starting with Maven?

I would like to specify the root context of my Java web application in my WAR file. How can I do this using valid `web-app` XML in a `web.xml` file?

Oh, yes I would like to do this in an application server agnostic way.

How do you specify the root context in your &lt;web-app&gt; tags in web.xml?

I am training in web developement and am learning about **JSP** &amp; **Servlets**. I have some knowledge of `HttpSession` - I have used it in some of my sample projects.

In browsers I have seen the option to &quot;delete cookies&quot;. If I delete the cookies it deletes the `HttpSession` also.

Are cookies and session the same? What are the differences between them?

Differences between cookies and sessions?

In a web-application implemented in java using JSP and Servlets; if I store information in the user session, this information is shared from all the tabs from the same browser. How to differ sessions in the browser-tabs? 
In this example: 

    &lt;%@page language=&quot;java&quot;%&gt;
    &lt;%
	String user = request.getParameter(&quot;user&quot;);
	user = (user == null ? (String)session.getAttribute(&quot;SESSIONS_USER&quot;) : user);
	session.setAttribute(&quot;SESSIONS_USER&quot;,user);
    %&gt;
    &lt;html&gt;&lt;head&gt;&lt;/head&gt;&lt;body&gt;
    &lt;%=user %&gt;
    &lt;form method=&quot;post&quot;&gt;
	User:&lt;input name=&quot;user&quot; value=&quot;&quot;&gt;
	&lt;input type=&quot;submit&quot; value=&quot;send&quot;&gt;
    &lt;/form&gt;
    &lt;/body&gt;&lt;/html&gt;

Copy this code in a jsp page (`testpage.jsp`), deploy this file in an existing context of a web application on the server (I use Apache Tomcat), then open a browser (FF, IE7 or Opera) using the correct URL (`localhost/context1/testpage.jsp`), type your name in the input and submit the form. Then open a new tab in the same browser, and then you can see your name (get from the session) on the new tab. Be careful with the browser-cache, sometimes seems that it doesn&#39;t happen, but it&#39;s in the cache, refresh the second tab.

Thanks.


How to differ sessions in browser-tabs?

Most of the places on the internet say it stands for **WEB INF**ormation.

I rather doubt it. The folder contains executables. **Information** is not a suitable name for it.

What does WEB-INF stand for in a Java EE web application?

By default, Tomcat sends some HTML content back to the client if it encounters something like an HTTP 404. I know that via `web.xml` an `&lt;error-page&gt;` [can be configured][1] to customize this content.

However, I&#39;d just like for Tomcat to **not send anything** in terms of response content (I&#39;d still like the status code, of course). Is there any way to easily configure this?

I&#39;m trying to avoid A) explicitly sending empty content on the response stream from my Servlet, and B) configuring custom error pages for a whole bunch of HTTP error statuses in my `web.xml`.

For some background, I&#39;m developing an HTTP API and am controlling my own response content. So for an HTTP 500, for example, I&#39;m populating some XML content on the response containing error information. For situations like an HTTP 404, the HTTP response status is sufficient for clients, and the content tomcat is sending is unnecessary. If there&#39;s a different approach, I&#39;m open to hearing it.

**Edit:**
After continued investigation, I still can&#39;t find much in the way of a solution. If someone can definitively say this is not possible, or provide a resource with evidence that it will not work, I&#39;ll accept that as an answer and try and work around it.

  [1]: http://wiki.apache.org/tomcat/FAQ/Miscellaneous#Q6

Disable all default HTTP error response content in Tomcat

I am getting a bit confused here. In our application we are having a few servlets defined. Here is the excerpt from the `web.xml` for one of the servlets:

&lt;!-- language: xml --&gt;

    &lt;servlet&gt;
		&lt;servlet-name&gt;AxisServlet&lt;/servlet-name&gt;
		&lt;display-name&gt;Apache-Axis Servlet&lt;/display-name&gt;
		&lt;servlet-class&gt;com.foo.framework.axis2.http.FrameworkServlet&lt;/servlet-class&gt;
		&lt;load-on-startup&gt;0&lt;/load-on-startup&gt;
	&lt;/servlet&gt; 


As per my understanding the value for the `&lt;load-on-startup&gt;` has to be a positive integer in order for it to get loaded automatically. I looked up on google but the responses I came across only added to my confusion.

What does the servlet &lt;load-on-startup&gt; value signify

What is the best web server for ruby on rails application? Why?

What is the best web server for Ruby on Rails application?

What is the difference between application server and web server?

I am using Nginx in front of 10 mongrels.

When I make a request with size larger then 2900 I get back an:

&gt; error code 414: uri too large

Does anyone know the setting in the nginx configuration file which determines the allowed uri length ?

How to set the allowed url length for a nginx request (error code: 414, uri too large)

How do I test if [memcache][1] or [memcached][2] (for PHP) is installed on my Apache webserver?

&gt; **Memcache** is a caching daemon designed especially for
dynamic web applications to decrease database load by
storing objects in memory.


  [1]: http://pecl.php.net/package/memcache
  [2]: http://pecl.php.net/package/memcached

How to check if memcache or memcached is installed for PHP?

I&#39;ve developed some web-based applications till now using PHP, Python and Java. But some fundamental but very important questions are still beyond my knowledge, so I made this post to  get help and clarification from you guys.

Say I use some programming language as my backend language(PHP/Python/.Net/Java, etc), and I deploy my application with a web server(apache/lighttpd/nginx/IIS, etc). And suppose at time T, one of my page got 100 simultaneous requests from different users. So my questions are:

 1. How does my web server handle such 100 simultaneous requests? Will web server generate one process/thread for each request? (if yes, process or thread?)
 2. How does the interpreter of the backend language do? How will it handle the request and generate the proper html? Will the interpreter generate a process/thread for each request?(if yes, process or thread?) 
 3. If the interpreter will generate a process/thread for each request, how about these processes(threads)? Will they share some code space? Will they communicate with each other? How to handle the global variables in the backend codes? Or they are independent processes(threads)? How long is the duration of the process/thread? Will they be destroyed when the request is handled and the response is returned?
 4. Suppose the web server can only support 100 simultaneous requests, but now it got 1000 simultaneous requests. How does it handle such situation? Will it handle them like a queue and handle the request when the server is available? Or other approaches?
 5. I read some articles about Comet these days. And I found long connection may be a good way to handle the real-time multi-users usecase. So how about long connection? Is it a feature of some specific web servers or it is available for every web server? Long connection will require a long-existing interpreter process?

---

EDIT: 
Recently I read some articles about CGI and fastcgi, which makes me know the approach of fastcgi should be a typical approach to hanlde request.

&gt; the protocol multiplexes a single transport connection between several independent FastCGI requests. This supports applications that are able to process concurrent requests using event-driven or multi-threaded programming techniques.

Quoted from [fastcgi spec][1], which mentioned *connection* which can handle several requests, and can be implemented in mutli-threaded tech. I&#39;m wondering this *connection* can  be treated as *process* and it can generate several *threads* for each request. If this is true, I become **more** confused about how to handle the shared resource in each thread?

P.S thank Thomas for the advice of splitting the post to several posts, but I think the questions are related and it&#39;s better to group them together.

Thank S.Lott for your great answer, but some answers to each question are too brief or not covered at all. 

Thank everyone&#39;s answer, which makes me closer to the truth.

  [1]: http://www.fastcgi.com/devkit/doc/fcgi-spec.html &quot;fastcgi spec&quot;

Some fundamental but important questions about web development?

How to set VM arguments for Jetty run from maven-jetty-plugin?

For example, I need to pass `-Xmx` arguments to Jetty run by the `mvn jetty:run` command.

How to control VM arguments for maven-jetty-plugin?

I&#39;m trying to make an &quot;executable&quot; war file (`java -jar myWarFile.war`) that will start up a Jetty webserver that hosts the webapp contained in the WAR file I executed.

I found [a page](http://eclipsesource.com/blogs/2009/10/02/executable-wars-with-jetty/) that described how to make what I&#39;m looking for:

However, following that advice along with how I think I&#39;m supposed to make an executable jar (war) isn&#39;t working.

I have an Ant task creating a WAR file with a manifest that looks like:

&gt;     Manifest-Version: 1.0
&gt;     Ant-Version: Apache Ant 1.7.1
&gt;     Created-By: 1.5.0_18-b02 (Sun Microsystems Inc.)
&gt;     Main-Class: Start

The contents of the WAR file look like:

    &gt; Start.class
    &gt; jsp
    &gt;   build.jsp 
    &gt; META-INF  
    &gt;   MANIFEST.MF
    &gt; WEB-INF
    &gt;   lib
    &gt;     jetty-6.1.22.jar
    &gt;     jetty-util.6.1.22.jar

When I try to execute the WAR file, the error is:

    Exception in thread &quot;main&quot; java.lang.NoClassDefFoundError: org/mortbay/jetty/Handler
    Caused by: java.lang.ClassNotFoundException: org.mortbay.jetty.Handler
            at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
            at java.security.AccessController.doPrivileged(Native Method)
            at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
            at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
            at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
            at java.lang.ClassLoader.loadClass(ClassLoader.java:248)
    Could not find the main class: Start. Program will exit.

There appears to be two errors here: one where it seems the JAR files can&#39;t be found, and one where the `Start` class can&#39;t be found.

To fix the first one, I put the Jetty JAR files in the base of the WAR file and tried again -- same error.  I also tried adding the `WEB-INF/lib/&lt;specific-JAR-files&gt;` to the `Class-Path` attribute of the manifest.  That did not work either.

Does anyone have any insight as to what I&#39;m doing right/wrong and how I can get this executable WAR file up and running?



Executable war file that starts jetty without maven

I am writing a web application using ring and clojure. I am using the jetty adapter for the development server and emacs/SLIME for IDE. While wrap-reload does help, run-jetty blocks my slime session and I would like to be able to start/stop it at will without having to run it in a separate terminal session. Ideally, I would like to define a server agent and functions start-server and stop-server that would start/stop the server inside the agent. Is this possible?

How do I stop jetty server in clojure?

What&#39;s the easiest way to debug Scala code managed by sbt using IntelliJ&#39;s built-in debugger? The documentation from [&quot;RunningSbt&quot; from sbt&#39;s google code site][1] lists commands for running the main class for a project or the tests, but there seem to be no commands for debugging.

Follow-up question: what&#39;s the easiest way to attach IntelliJ&#39;s debugger to Jetty when using sbt&#39;s jetty-run command?

[1]:http://code.google.com/p/simple-build-tool/wiki/RunningSbt

Content Type	Original Author	Original Content on Stackoverflow
Question	Loki	View Question on Stackoverflow
Solution 1 - Java	Vinko Vrsalovic	View Answer on Stackoverflow
Solution 2 - Java	Jimmy Subb	View Answer on Stackoverflow
Solution 3 - Java	Andrew Swan	View Answer on Stackoverflow

Tomcat VS Jetty

Java Problem Overview

Java Solutions

Solution 1 - Java

Solution 2 - Java

Solution 3 - Java

Why should I declare a virtual destructor for an abstract class in C++?

Object-orientation in C

Attributions