Intellij Error: “Usage of API documented as @since 1.8+..”

Solution#1:

Add Java version in properies section of pom.xml

    <properties>
        ......
        <maven.compiler.source>1.8</maven.compiler.source>
        <maven.compiler.target>1.8</maven.compiler.target>
    </properties>

   
Solution#2:

You have to add build configuration in your pom.xml

    <build>
        .....
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.8.1</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>
        </plugins>
    </build>

Solution#3: For IntelliJ users, add the following configuration.
Use both Solution#1 and Solution#2, Then add settings like below:

File -> Project Structure -> Project Settings -> Modules -> "Your Module Name" -> Sources -> Language Level

and change to your desired level i.e 1.8 or others.