Failed to execute goal org.apache.maven.plugins:maven-javadoc-plugin:3.2.0:jar (default) code example

Example 1: Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.1:compile (default-compile) on project electronicbookshop: Compilation failure

<plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>2.4</version>
            <configuration>
                <source>1.8</source>
                <target>1.8</target>
</configuration>
</plugin>

Example 2: Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.6.1:compile (default-compile) on project a2: Compilation failure [ERROR] No compiler is provided in this environment. Perhaps you are running on a JRE rather than a JDK?

set JAVA_HOME=<ABSOLUTE_PATH_TO_JDK>