Set JDK 1.6 in IntelliJ IDE

1.
Install JDK1.6 (/System/Library/Java/JavaVirtualMachines/1.6.0.jdk/)
Right Click "selected Project" -> Open Module Settings -> Project -> Project SDK->JDK1.6

In pom.xml, add maven-compiler-plugin

<artifactId>yourproject</artifactId>

<build>

<plugins>

<plugin>

<groupId>org.apache.maven.plugins</groupId>

<artifactId>maven-compiler-plugin</artifactId>

<version>3.0</version>

<configuration>

<source>1.6</source>

<target>1.6</target>

</configuration>

</plugin>

</plugins>

</build>

<version>0.0.1-SNAPSHOT</version>

2. Generate .jar by using Maven from IntelliJ

Maven Projects->package->Right click "Run Maven Build"
Find the jar file from "~/IdeaProjects/projectname/target/"