If you really want to identify and call the methods directly you could use reflection. Something like (with no exception management):
```java SomeObject object = ...; Class<?> type = object.getClass(); for (Method method : type.getMethods()) { JsonProperty property = method.getAnnotation(JsonProperty.class); if (property != null && property.value().equals("value")) { if (method.getParameterCount() == 0) { Object value = method.invoke(object); ... } } } ```

Just out of curiosity I've taken a look at what happens under the hood, and I've used [dtruss/strace][1] on each test.
C++
./a.out < in Saw 6512403 lines in 8 seconds. Crunch speed: 814050
syscalls `sudo dtruss -c ./a.out < in`
CALL COUNT __mac_syscall 1 <snip> open 6 pread 8 mprotect 17 mmap 22 stat64 30 read_nocancel 25958

Python
./a.py < in Read 6512402 lines in 1 seconds. LPS: 6512402
syscalls `sudo dtruss -c ./a.py < in`
CALL COUNT __mac_syscall 1 <snip> open 5 pread 8 mprotect 17 mmap 21 stat64 29
[1]: http://en.wikipedia.org/wiki/Strace