[FIXED] Unable to import any javax-servlet in Maven project in Netbeans

Issue

I am making a Maven project it is my first time with Maven. I'm using Netbeans and Tomcat server and I am not able to import any javax.servlet e.g. import javax.servlet.RequestDispatcher; etc. It looks like that:

There is info: javax.servlet does not exist and a solution proposed by Netbeans is for example: "Search Dependency at Maven Repository for javax.servlet.RequestDispatcher. When I click it then there is a pop-up window without anything to do:

I have the pom.xml file located in C://pathToNetbeansProjects/myProject/pom.xml and I added a dependency for javax-servlet now my pom.xml looks like this:

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">

<modelVersion>4.0.0</modelVersion>

<groupId>org.glassfish.jersey.archetypes</groupId>
<artifactId>ParkingSystem</artifactId>
<packaging>war</packaging>
<version>1.0-SNAPSHOT</version>
<name>ParkingSystem</name>

<build>
    <finalName>ParkingSystem</finalName>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>2.5.1</version>
            <inherited>true</inherited>
            <configuration>
                <source>1.7</source>
                <target>1.7</target>
            </configuration>
        </plugin>
    </plugins>
</build>

<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>org.glassfish.jersey</groupId>
            <artifactId>jersey-bom</artifactId>
            <version>${jersey.version}</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
    </dependencies>
</dependencyManagement>

<dependencies>
    <dependency>
        <groupId>org.glassfish.jersey.containers</groupId>
        <artifactId>jersey-container-servlet-core</artifactId>
        <!-- use the following artifactId if you don't need servlet 2.x compatibility -->
        <!-- artifactId>jersey-container-servlet</artifactId -->
    </dependency>
    <dependency>
        <groupId>org.glassfish.jersey.inject</groupId>
        <artifactId>jersey-hk2</artifactId>
    </dependency>
    <!-- uncomment this to get JSON support -->
    <dependency>
        <groupId>org.glassfish.jersey.media</groupId>
        <artifactId>jersey-media-json-binding</artifactId>
    </dependency>
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>javax.servlet-api</artifactId>
        <version>4.0.1</version>
        <scope>provided</scope>
    </dependency>       
</dependencies>

<properties>
    <jersey.version>2.27</jersey.version>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>

I have no more ideas if I am doing something wrong with my pom.xml or maybe I need to do something in Netbeans to make it work. But I don't know really what.

Solution

The problem is 99% caused by a different import done by Maven on that library. Maven imports your libs following a hierarchical manner, so probably there's some lib that you have imported that contains the javax.servlet, but it's not the version that you need.

First I suggest you to looking for which one is doing that for resolving the conflict by looking into maven hierarchy, you can achieve this with console command mvn dependency:tree -Dverbose ( look here for an example).

Then you can omit the unwanted libraries by a specific maven command inside your library:

<dependency>
....

    <exclusions> 
        <exclusion>
            <groupId>javax.servlet</groupId>
            <artifactId>servlet-api</artifactId>
        </exclusion>
    </exclusions> 

</dependency>

This is an explanation useful for understanding "why" is happening this, so you can understand it.

Btw a quick fix, that you can try as first instance, is moving the import you wanted javax.servlet as first element of your pom.

Answered By - Leviand
Answer Checked By - Senaida (JavaFixing Volunteer)