This only allows Java 7 language features, and you can hardly benefit from anything since a half of improvement also comes from the library. Features you could use are those which do not depend on the library:
- Diamond operator
<> - String switch
- Multiple-catch
catch (Exc1 | Exc2 e) - Underscore in number literals
1_234_567 - Binary literals
0b1110111
And these features cannot be used yet:
- The try-with-resources statement — because it requires the non-existing interface
java.lang.AutoCloseable(this can be used publicly in 4.4+) - The
@SafeVarargsannotation — becausejava.lang.SafeVarargsdoes not exist