Develop Reference

springboot embedded tomcat and tomcat-embed-jasper

I sometimes see these following declaration in pom.xml...
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>jstl</artifactId>
</dependency>
<dependency>
<groupId>org.apache.tomcat.embed</groupId>
<artifactId>tomcat-embed-jasper</artifactId>
<scope>provided</scope>
</dependency>
....
as you can see, spring-boot-starter-web was declared as well
as tomcat-embed-jasper.
isn't it spring-boot-starter-web already have an embedded tomcat?
why some developers still declare tomcat-embed-jasper along with boot-starter-web? or is there any reason?

As you said, the spring-boot-starter-web includes the spring-boot-starter-tomcat. You could check it here
The spring-boot-starter-tomcat includes the tomcat-embed-core. You could check it here
But, seems like tomcat-embed-core doesn't include tomcat-embed-jasper. In fact, is tomcat-embed-jasper who includes dependency with tomcat-embed-core. Check it here
Anyway, the tomcat-embed-jasper is marked as provided, so indicates that you expect the JDK or a container to provide the dependency at runtime. This scope is only available on the compilation and test classpath, and is not transitive.
In conclusion, the spring-boot-starter-web includes the tomcat embedded dependency but it doesn't includes the jasper embedded dependency, so that should be the reason to declare it separately.
Also, remember that using Spring IO Platform as parent you are able to manage dependencies easily. To know more about this you could read my post
Hope it helps,

Extended from jcgarcia's answer.
Even it is provided, but when you build as war, spring-boot-maven-plugin will include two more jar :
ecj-3.12.3.jar
tomcat-embed-jasper-8.5.23.jar

To those who are still facing this error in 2022 with Java Version 17, Maven Version 3.0.0 and Package Jar. I also ran into the same issue just now, seems like even though we set <scope>Provided</scope> Maven is not picking up the jar. What you can do instead is just take that completely off while adding the dependency and run the Maven to install dependencies again. It will fix it for sure. So your pom.xml file will go:-
From
<dependency>
<groupId>org.apache.tomcat.embed</groupId>
<artifactId>tomcat-embed-jasper</artifactId>
<scope>provided</scope>
</dependency>
To
<dependency>
<groupId>org.apache.tomcat.embed</groupId>
<artifactId>tomcat-embed-jasper</artifactId>
</dependency>

Isn't web.xml supposed to be included when building maven project ? NetBeans

I made a new Maven project with Netbeans. There is a pom.xml in which i added:
<dependencies>
<dependency>
<groupId>javax</groupId>
<artifactId>javaee-web-api</artifactId>
<version>7.0</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>4.2.4.RELEASE</version>
</dependency>
<dependency>
<groupId>org.apache.struts</groupId>
<artifactId>struts2-core</artifactId>
<version>2.3.24</version>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-core</artifactId>
<version>5.1.0.Final</version>
</dependency>
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.14</version>
</dependency>
</dependencies>
Is it normal if I don't have a web.xml in my project tree after building the project or should i treat the glassfish.xml just the same ?
I wonder if I didn't messed up things.

Java EE 6 made web.xml optional (traded in for a bunch of annotation-based configurations).
If maven knows that Java EE 6 is the version, then it won't complain about a missing web.xml.
You should be able to configure for the most part using annotations. For portability's sake, use web.xml IF NEEDED rather than relying on vendor-specific configuration files.

Yup I Got solution (how to create web.xml in maven NetBeans 12.0 or later)
After making web application in maven NetBeans
1) Right click on WEB-INF Folder -> New -> Other
after clicking on other.. a window will popup
in that choose : WEB folder in category
after choosing WEB on right corresponding file type will open
in that select: Standard Deployment Descriptor(web.xml)
and now u have it enjoy .....
[My first Answer on Stack Overflow :)]

Single/complete Maven dependencies for Java EE 5 API

Is there a single maven dependency containing whole Java EE 5 spec API. Just like
<dependency>
<groupId>javax</groupId>
<artifactId>javaee-api</artifactId>
<version>6.0</version>
</dependency>
for Java EE 6.
I'm using JBoss 5 and want to add single (or several) dependency as provided scope and be sure that I have everyting that is available in JBoss.
Maybe some kind of archetype exist for JBoss 5.x.x deployed project?

Based on maven central I think you need the following:
<dependency>
<groupId>javaee</groupId>
<artifactId>javaee-api</artifactId>
<version>5</version>
</dependency>

Writing Maven Dependency for javax.persistence

Can someone help me write the dependency for javax.persistence. I have googled it but nothing worked.
I bumped into this page that gives some details on how to write the dependency, but yet i am unable to write it. Can someone help me out?

This is the one for javax.persistence:
<dependency>
<groupId>javax.persistence</groupId>
<artifactId>persistence-api</artifactId>
<version>1.0.2</version>
<scope>provided</scope>
</dependency>
and this is for the whole Java EE 6 stack:
<dependency>
<groupId>javax</groupId>
<artifactId>javaee-api</artifactId>
<version>6.0</version>
<scope>provided</scope>
</dependency>
Edit
Note that I specified a provided scope here, which means that your dependency is available at compile- and test-time, but will not be packaged into your artifacts. This is usually needed if you want to deploy your artifacts in an application server, since they provide their own implementation of the api.

And add this dependency in your pom.xml:
<dependency>
<groupId>javax.persistence</groupId>
<artifactId>persistence-api</artifactId>
<version>1.0.2</version>
</dependency>
That "Coping with Sun JARs" page might be a little outdated, this JAR is available in the Maven Central Repository

Updated link:
https://mvnrepository.com/artifact/javax.persistence/javax.persistence-api/2.2 is here.
and the maven dependency is as below:
<dependency>
<groupId>javax.persistence</groupId>
<artifactId>javax.persistence-api</artifactId>
<version>2.2</version>
</dependency>

For the latest versions javax.persistance is not working instead of that we can use jakarta.persistence to create an entity or resolve the error Cannot resolve symbol 'Entity'. For that need to add the dependency
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-core</artifactId>
<version>6.1.6.Final</version>
<type>pom</type>
</dependency>

java ee api is missing on project classpath while using httpunit for servlet testing in maven

I want to run the servlet testing example available here using maven. Javaee web api should be declared as provided:
<dependency>
<groupId>javax</groupId>
<artifactId>javaee-web-api</artifactId>
<version>6.0</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>httpunit</groupId>
<artifactId>httpunit</artifactId>
<version>1.7</version>
<scope>test</scope>
</dependency>
However, one of the tests in the example throws ServletException. NetBeans complains that java ee api is missing on project classpath. How does one solve this issue?
EDIT
It is not a NetBeans issue, it is a maven issue.

Now this is the most debilitating issue I have ever faced in my Java days. And it is followed by the most ridiculous workaround I have ever seen, ever:
<dependency>
<groupId>httpunit</groupId>
<artifactId>httpunit</artifactId>
<version>1.7</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>javax</groupId>
<artifactId>javaee-web-api</artifactId>
<version>6.0</version>
<scope>provided</scope>
</dependency>
Yes, permute the declaration of dependencies in the pom.xml (see here for "why") and make javaee-web-api last.

It means that maven (or netbeans...I haven't used netbeans in 10 years), couldn't download or find that artifact in the local repository.
The scope provided means: I need the jar to compile my source code, but don't bundle the jar in the final package.