IntelliJ IDEA 13 uses Java 1.5 despite setting to 1.7

Question

Despite specifying JDK 1.7 in all project settings (including in File -> Project Structure -> Project :: Project SDK), the following error is produced by

Answer 1

I tried making changes to Intellij IDEA as below:

1.

File >> Settings >> Build, Execution, Deployment >> Compiler >> Java Compiler >> project bytecode version: 1.8 >> Per-module bytecode version: 1.8

2.

File >> Project Structure >> Project Settings >> Project >> SDK : 1.8, Project Language : 8 - Lambdas
File >> Project Structure >> Project Settings >> Modules >> abc : Language level: 8 - Lambdas

but nothing worked, it reverted the versions to java 1.5 as soon as I saved it.

However, adding below lines to root(project level) pom.xml worked me to resolve above issue: (both of the options worked for me)

Option 1:

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

Option 2:

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