This functionality has been [implemented](https://git-wip-us.apache.org/repos/asf?p=maven.git;a=commitdiff;h=ee7dbab69dd87d219031b0715105527cdbf12639;hp=cd52e5b51e8e986b6daea8c0b56dd61968410695) as [MNG-5768][1], and is available in Maven 3.3.1.

The change will:
&gt; extend direct plugin invocation syntax to allow optional @execution-id parameter, e.g., org.apache.maven.plugins:maven-remote-resources-plugin:1.0:process@executionId.

So, in your case:

    mvn antrun:run

uses the `default-cli` execution ID, and:

    mvn antrun:run@my-execution

uses the execution configured in your pom.


  [1]: https://issues.apache.org/jira/browse/MNG-5768

The most direct means of executing your maven plugin is to specify the plugin goal directly on the command line.

    mvn groupId:artifactId:version:goal

More information at: [Development guide for Maven plugins][1]


  [1]: http://maven.apache.org/guides/plugin/guide-java-plugin-development.html

What you&#39;re looking for is captured in [Default+Plugin+Execution+IDs][1] but to my knowledge currently not supported. However, according to the comments of [MNG-3401][2] (read them until the end):

&gt; for mojos invoked directly from the
&gt; command line, you can supply
&gt; configuration from the POM using the
&gt; executionId: &#39;default-cli&#39; like this:
&gt; 
&gt;     &lt;plugin&gt;
&gt;       &lt;artifactId&gt;maven-assembly-plugin&lt;/artifactId&gt;
&gt;       &lt;executions&gt;
&gt;         &lt;execution&gt;
&gt;           &lt;id&gt;default-cli&lt;/id&gt;
&gt;           &lt;configuration&gt;
&gt;             &lt;descriptorRefs&gt;
&gt;               &lt;descriptorRef&gt;jar-with-dependencies&lt;/descriptorRef&gt;
&gt;               &lt;descriptorRef&gt;project&lt;/descriptorRef&gt;
&gt;             &lt;/descriptorRefs&gt;
&gt;           &lt;/configuration&gt;
&gt;         &lt;/execution&gt;
&gt;       &lt;/executions&gt;
&gt;     &lt;/plugin&gt;
&gt; 
&gt; This should work in Maven 2.2.0 and
&gt; 3.x.

Maybe this will be enough for you.


  [1]: https://web.archive.org/web/20150504113922http://docs.codehaus.org/display/MAVENUSER/Default+Plugin+Execution+IDs
  [2]: https://issues.apache.org/jira/browse/MNG-3401

In my ASP.NET application, I was trying to add few white spaces between two text boxes by typing space bar. The equivalent HTML source was `&amp;#160;` instead of `&amp;nbsp;`. So I just wanted to check: is this the new replacement for white space? If yes, any idea why they changed?


Is &quot;&amp;#160;&quot; a replacement of &quot;&amp;nbsp;&quot;?

[Note: This question had the original title &quot;__C (ish) style union in C#__&quot;
but as Jeff&#39;s comment informed me, apparently this structure is called a &#39;discriminated union&#39;]


Excuse the verbosity of this question.

There are a couple of similar sounding questions to mine already in SO but they seem to concentrate on the memory saving benefits of the union or using it for interop.
[Here is an example of such a question][1].

My desire to have a union type thing is somewhat different.

I am writing some code at the moment which generates objects that look a bit like this

    public class ValueWrapper
    {
        public DateTime ValueCreationDate;
        // ... other meta data about the value

        public object ValueA;
        public object ValueB;
    }

Pretty complicated stuff I think you will agree.  The thing is that `ValueA` can only be of a few certain types (let&#39;s say `string`, `int` and `Foo` (which is a class) and `ValueB` can be another small set of types.  I don&#39;t like treating these values as objects (I want the warm snugly feeling of coding with a bit of type safety).  

So I thought about writing a trivial little wrapper class to express the fact that ValueA logically is a reference to a particular type.  I called the class `Union` because what I am trying to achieve reminded me of the union concept in C.


    public class Union&lt;A, B, C&gt;
    {
        private readonly Type type; 
        public readonly A a;
        public readonly B b;
        public readonly C c;

        public A A{get {return a;}}
        public B B{get {return b;}}
        public C C{get {return c;}}

        public Union(A a)
        {
            type = typeof(A);
            this.a = a;
        }

        public Union(B b)
        {
            type = typeof(B);
            this.b = b;
        }

        public Union(C c)
        {
            type = typeof(C);
            this.c = c;
        }

        /// &lt;summary&gt;
        /// Returns true if the union contains a value of type T
        /// &lt;/summary&gt;
        /// &lt;remarks&gt;The type of T must exactly match the type&lt;/remarks&gt;
        public bool Is&lt;T&gt;()
        {
            return typeof(T) == type;
        }

        /// &lt;summary&gt;
        /// Returns the union value cast to the given type.
        /// &lt;/summary&gt;
        /// &lt;remarks&gt;If the type of T does not exactly match either X or Y, then the value &lt;c&gt;default(T)&lt;/c&gt; is returned.&lt;/remarks&gt;
        public T As&lt;T&gt;()
        {
            if(Is&lt;A&gt;())
            {
                return (T)(object)a;    // Is this boxing and unboxing unavoidable if I want the union to hold value types and reference types? 
                //return (T)x;          // This will not compile: Error = &quot;Cannot cast expression of type &#39;X&#39; to &#39;T&#39;.&quot;
            }

            if(Is&lt;B&gt;())
            {
                return (T)(object)b; 
            }

            if(Is&lt;C&gt;())
            {
                return (T)(object)c; 
            }

            return default(T);
        }
    }


Using this class ValueWrapper now looks like this

    public class ValueWrapper2
    {
        public DateTime ValueCreationDate;
        public  Union&lt;int, string, Foo&gt; ValueA;
        public  Union&lt;double, Bar, Foo&gt; ValueB;
    }

which is something like what I wanted to achieve but I am missing one fairly crucial element - that is compiler enforced type checking when calling the Is and As functions as the following code demonstrates

        public void DoSomething()
        {
            if(ValueA.Is&lt;string&gt;())
            {
                var s = ValueA.As&lt;string&gt;();
                // .... do somethng
            }

            if(ValueA.Is&lt;char&gt;()) // I would really like this to be a compile error
            {
                char c = ValueA.As&lt;char&gt;();
            }
        }


IMO It is not valid to ask ValueA if it is a `char` since its definition clearly says it is not - this is a programming error and I would like the compiler to pick up on this.  [Also if I could get this correct then (hopefully) I would get intellisense too - which would be a boon.]  

In order to achieve this I would want to tell the compiler that the type `T` can be one of A, B or C

        public bool Is&lt;T&gt;() where T : A 
                               or T : B // Yes I know this is not legal!
                               or T : C 
        {
            return typeof(T) == type;
        } 

Does anyone have any idea if what I want to achieve is possible?  Or am I just plain stupid for writing this class in the first place?

Thanks in advance.


  [1]: https://stackoverflow.com/questions/126781/c-union-in-c

Discriminated union in C#

I have a plugin (antrun) with an execution configured which has an id and is not bound to any phase. Can I execute this execution directly from the command line? 

    &lt;plugin&gt;
      &lt;artifactId&gt;maven-antrun-plugin&lt;/artifactId&gt;
      &lt;executions&gt;
        &lt;execution&gt;
          &lt;id&gt;my-execution&lt;/id&gt;
          ...
        &lt;/execution&gt;
      &lt;/executions&gt;
    &lt;/plugin&gt;

An run it with something like:
    
    mvn my-execution

or at least

    mvn magicplugin:execute -DexecutionId=my-execution

How to execute maven plugin execution directly from command line?

I have a plugin (antrun) with an execution configured which has an id and is not bound to any phase. Can I execute this execution directly from the command line?
<pre><code class="hljs language-php-template">&#x3C;plugin>
 &#x3C;artifactId>maven-antrun-plugin&#x3C;/artifactId>
 &#x3C;executions>
 &#x3C;execution>
 &#x3C;id>my-execution&#x3C;/id>
 ...
 &#x3C;/execution>
 &#x3C;/executions>
&#x3C;/plugin>
</code></pre>
An run it with something like:
<pre><code class="hljs language-perl">mvn my-execution
</code></pre>
or at least
<pre><code class="hljs language-ini">mvn magicplugin:execute -DexecutionId=my-execution
</code></pre>

I&#39;m trying to figure out how to organize many (around 50+) maven2 projects, so that they can deploy into a central nexus repository. When using the `mvn deploy` goal, one does need to specify the target in the distributionManagement tag like this:

    &lt;distributionManagement&gt;
       &lt;repository&gt;
          &lt;id&gt;nexus-site&lt;/id&gt;
        	&lt;url&gt;http://central_nexus/server&lt;/url&gt;
       &lt;/repository&gt;
    &lt;/distributionManagement&gt;

Now, i don&#39;t want every single pom.xml (of those 50+) to contain this block over and over again. My first though would be the `settings.xml` file, but it seems it is not possible (by design) to define it there. 
So, the first question would be, why is that the case ? If it would be possible i could specify it in the settings.xml in the maven2 distribution, which could be distributed to all developers.

The only possible solution i&#39;ve found was to create an organisation-wide master-pom project, that does contain these settings, and make all other pom.xml depend on this master-pom via `&lt;parent&gt;` tag. But this looks kind of strange in multi-module builds:

    - master configuration POM (pm)
    - Project 1 parent pom (p1 with module 1 and module 2 as modules)
        - Project 1 module pom (with pm as parent)
        - Project 2 module pom (with pm as parent)

Usually i read in all documentation that the module poms should use the parent pom, not some different one. But after reading the maven website about Inheritance v. Aggregation it is written that it is indeed possible.

One problem i found was with the maven site generation, which does seem to have problems with this setup (modules does not get linked correctly if they have no direct back-reference)

So, is this a valid approach ? Any other, more obvious, simpler solution to the problem ?


How to specify maven&#39;s distributionManagement organisation wide?

I am fairly new to Maven and pom.xml. Is there a way I can find out which of my dependencies that are outdated, so that I can update version numbers in my pom.xml.

In other languages, for instance, Ruby has the command `gem list outdated` that gives me a list of dependencies (rubygems) I can update


I am using IntelliJ Idea if that can help.



How to check pom.xml for updated dependencies

What are the main benefits of using maven compared to let&#39;s say ant ?
It seems to be more of a annoyance than a helpful tool.
I use maven 2, with plain Eclipse Java EE (no m2eclipse), and tomcat.

Supporters of maven believe that 

1. Maven lets you get your package dependencies easily

2. Maven forces you to have a standard directory structure

In my experience

1. Figuring out package dependencies is really not that hard. You rarely do it anyway. Probably once during project setup and few more during upgrades. With maven you&#39;ll end up fixing mismatched dependencies, badly written poms, and doing package exclusions anyway.

2. Slow FIX-COMPILE-DEPLOY-DEBUG cycle, which kills productivity. This is my main gripe. You make a change, the you have to wait for maven build to kick in and wait for it to deploy. No hot deployment whatsoever.

Or am I just doing it wrong ? Please point me to the right direction, I&#39;m all ears.

Why maven? What are the benefits?

I&#39;ve been using maven for a while, and I often review repositories before selected what version I want to use.  I don&#39;t entirely understand what the extensions mean.

I know that when I see extensions like -RC1 and -RC2 that means release candidates.   When I see a version without an extension, I assume that means a released version.  But what does an extension of -M1 or -M2 mean?

Example:

2.8-RC1

2.8

2.8-M1  ??

What does M1 mean in a maven repository?

What is the simplest way to retrieve version number from maven&#39;s pom.xml in code, i.e., programatically?

Retrieve version from maven pom.xml in code

In projects with several dependencies and repositories, the try-and-error approach of Maven for downloading dependencies is a bit cumbersome and slow, so I was wondering if there is any way to set an specific repo for some declared dependencies.

For example, I want for bouncycastle to check directly BouncyCastle&#39;s Maven repo at http://repo2.maven.org/maven2/org/bouncycastle/ instead of official Maven.

How to specify a repository for a dependency in Maven

Is there a way ( I mean how do I ) set a system property in a maven project?


I want to access a property from my test and my webapp ( running locally ) and I know I can use a java system property. 


Should I put that in ./settings.xml or something like that?

&lt;b&gt;Context&lt;/b&gt;

I took an open source project and managed to change the db configuration to use JavaDB


Now, in the jdbc url for JavaDB, the location of the database could be specified as the full path ( see: [this other question][1] ) 

Or a system property: `derby.system.home`

I have the code working already, but currently it is all hardcoded to: 


     jdbc:derby:/Users/oscarreyes/javadbs/mydb

And I want to remove the full path, to leave it like:

     jdbc:derby:mydb

To do that I need to specify the system property ( `derby.system.home` ) to maven, but I don&#39;t know how. 

The test are performed using junit ( I don&#39;t see any plugin in pom.xml ) and the web app runs with the jetty plugin. 


Specifying the system property in the command line seems to work for jetty, but I&#39;m not sure if that&#39;s something practical ( granted some other users may run it from eclipse/idea/ whatever ) 


  [1]: https://stackoverflow.com/questions/3231614/javadb-derby-path-to-database

Specify system property to Maven project

How can I change the name from `1.0.snapshot-jar-with-dependencies` to something else, below are contents of my POM:

	
&lt;!-- language: lang-xml --&gt;

    &lt;build&gt;
		&lt;plugins&gt;
   			&lt;plugin&gt;
   				&lt;artifactId&gt;maven-assembly-plugin&lt;/artifactId&gt;
  				&lt;version&gt;2.2-beta-5&lt;/version&gt;
   				&lt;configuration&gt;
   					&lt;archive&gt;
   						&lt;manifest&gt;
   							&lt;mainClass&gt;com.package.example.MainClass&lt;/mainClass&gt;
   						&lt;/manifest&gt;
   					&lt;/archive&gt;
   					&lt;descriptorRefs&gt;
   						&lt;descriptorRef&gt;jar-with-dependencies&lt;/descriptorRef&gt;
   					&lt;/descriptorRefs&gt;
   				&lt;/configuration&gt;
   			&lt;/plugin&gt;
   		&lt;/plugins&gt;
   	&lt;/build&gt;

How can I change the war name generated by maven assembly plugin

&lt;!-- language-all: xml --&gt;

I have a web application Maven project, and I want to customize the web.xml file depending on the Profile that is running. I am using the Maven-War-plugin, which allows me to define a &quot;resources&quot; directory, where the files may be filtered. However, filtering alone is not sufficient for me.

In more detail, I want to **include (or exclude)** the whole section on security, depending on the profile I an running. This is the part:

    ....
    ....
	
	&lt;security-constraint&gt;
	
		&lt;web-resource-collection&gt;
			&lt;web-resource-name&gt;protected&lt;/web-resource-name&gt;
			&lt;url-pattern&gt;/pages/*.xhtml&lt;/url-pattern&gt;
			&lt;url-pattern&gt;/pages/*.jsp&lt;/url-pattern&gt;
		&lt;/web-resource-collection&gt;
		
		&lt;auth-constraint&gt;
			&lt;role-name&gt;*&lt;/role-name&gt;
		&lt;/auth-constraint&gt;
		
		&lt;/security-constraint&gt;
			&lt;login-config&gt;
			&lt;auth-method&gt;${web.modules.auth.type}&lt;/auth-method&gt;
			&lt;realm-name&gt;MyRealm&lt;/realm-name&gt;
		&lt;/login-config&gt;

	&lt;security-constraint&gt;

    ....
    ....

If this is not done easily, is there a way to have two web.xml files and select the appropriate one depending on the profile?


Content Type	Original Author	Original Content on Stackoverflow
Question	artemb	View Question on Stackoverflow
Solution 1 - Maven	Joe	View Answer on Stackoverflow
Solution 2 - Maven	Dimitri Dewaele	View Answer on Stackoverflow
Solution 3 - Maven	Pascal Thivent	View Answer on Stackoverflow

How to execute maven plugin execution directly from command line?

Maven Problem Overview

Maven Solutions

Solution 1 - Maven

Solution 2 - Maven

Solution 3 - Maven

Discriminated union in C#

Is " " a replacement of " "?

Attributions