JDK 8 compiler fails if referenced final variable is not being called with "this."

FooBar.java

/**
 * @author bruno.borges@oracle.com
 */
public class FooBar {

    private final String foobar;

    public FooBar() {
        foobar = "foobar";
    }

    private final java.util.function.Function ds = n -> {
        System.out.println(this.foobar); // compiles successfuly
        System.out.println(foobar); // throws compilation error: "variable foobar might not have been initialized"

        return foobar;
    };

}