# Future, CompletableFuture
Below described a problem, when several Futures are submitted and you try to wait for them using `.get()` in a loop. There is no guarantee which will be the order of all these Futures execution. So your main thread will wait until your first Future in a loop will return anything:
## Completable future
```java
Supplier supplier = () -> "Hello";
CompletableFuture future = CompletableFuture.supplyAsync(supplier);
future.join(); // this is a blocking code
```
### ofAll
{% code fullWidth="true" %}
```java
CompletableFuture future1 = CompletableFuture.supplyAsync(new WeatherRetriever()::getWeather);
CompletableFuture future2 = CompletableFuture.supplyAsync(new WeatherRetriever()::getWeather);
CompletableFuture future3 = CompletableFuture.supplyAsync(new WeatherRetriever()::getWeather);
CompletableFuture done = CompletableFuture.allOf(future1, future2, future3);
done.thenApply( v -> Stream.of(future1, future2, future3)
// this is kind of blocking, but at this moment all futures are completed
.map(CompletableFuture::join)
).join();
```
{% endcode %}
### Composing results of futures
{% code fullWidth="true" %}
```java
CompletableFuture jumpFuture = CompletableFuture.supplyAsync(Jumper::jump);
CompletableFuture swimFuture = CompletableFuture.supplyAsync(Swimmer::swim);
SportResult result = jumpFuture.thenCompose(
jumpResult -> swimFuture.thenApply(
swimResult -> new SportResult(jumpResult, swimResult)
)
).join();
```
{% endcode %}
