idea lambda expressions are not supported in -source 1.5

java-8-maven-idea.md

When using lambda in a Maven based project in IntelliJ IDEA, got

idea lambda expressions are not supported in -source 1.5

solved by add this in pom file:

<build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.3</version>
            <configuration>
                <source>1.8</source>
                <target>1.8</target>
            </configuration>
        </plugin>
    </plugins>
</build>