Generate War file using Maven

First you must define your project with as packaging of war type:

<groupId>...</groupId>
<artifactId>...</artifactId>
<version>...</version>
<packaging>war</packaging>

Then you will need to use the maven plugin to generate the war when compiling:

<plugin>
    <artifactId>maven-war-plugin</artifactId>
    <configuration>
        <attachClasses>true</attachClasses>
        <webXml>target/web.xml</webXml>
        <webResources>
            <resource>
                <directory>src/main/webapp</directory>
                <filtering>true</filtering>
            </resource>
        </webResources>
    </configuration>
</plugin>

Try running clean install or clean package maven command.

Project > run as > run config > maven build in left panel > right click > new > goal > clean install > base directory> select your current project workspace.> apply> run

same way for clean package or any other maven command.

if it gives BUILD SUCCESS then fine otherwise put that error code here in the question.

one solution is just to use a maven-war-plugin(https://maven.apache.org/plugins/maven-war-plugin/index.html)