specify the Java compiler version in pom.xml

For example, if you want to use the Java 8 language features (-source 1.8) and also want the compiled classes to be compatible with JVM 1.8 (-target 1.8), you can either add the two following properties, which are the default property names for the plugin parameters:

<project>
  [...]
  <properties>
    <maven.compiler.source>1.8</maven.compiler.source>
    <maven.compiler.target>1.8</maven.compiler.target>
  </properties>
  [...]
</project>

or configure the plugin directly:

<project>
  [...]
  <build>
    [...]
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-compiler-plugin</artifactId>
        <version>3.7.0</version>
        <configuration>
          <source>1.8</source>
          <target>1.8</target>
        </configuration>
      </plugin>
    </plugins>
    [...]
  </build>
  [...]
</project>

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How do you specify the Java compiler version in a pom.xml file?
@reference_2_stackoverflow.com
Specifying java version in maven - differences between properties and compiler plugin
@reference_3_maven.apache.org
Setting the -source and -target of the Java Compiler

Can't execute jar- file: “no main manifest attribute”

For Maven, something like the following snippet should do the trick. Note that this is only the plugin definition, not the full pom.xml:

<build>
  <plugins>
    <plugin>
      <!-- Build an executable JAR -->
      <groupId>org.apache.maven.plugins</groupId>
      <artifactId>maven-jar-plugin</artifactId>
      <version>3.0.2</version>
      <configuration>
        <archive>
          <manifest>
            <addClasspath>true</addClasspath>
            <classpathPrefix>lib/</classpathPrefix>
            <mainClass>com.mypackage.MyClass</mainClass>
          </manifest>
        </archive>
      </configuration>
    </plugin>
  </plugins>
</build>

@reference_1_stackoverflow.com

Eclipse/Maven error: “No compiler is provided in this environment”

Go to Window → Preferences → Java → Installed JREs.

And see if there is an entry pointing to your JDK path, and if not, click on Edit button and put the path you configured your JAVA_HOME environment.

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