src/main/java/io/reactivex/Observable.java
@CheckReturnValue
    @SchedulerSupport(SchedulerSupport.NONE)
    public final Disposable subscribe(Consumer<? super T> onNext) {
        return subscribe(onNext, Functions.ON_ERROR_MISSING, Functions.EMPTY_ACTION, Functions.emptyConsumer());
    }
@CheckReturnValue
    @SchedulerSupport(SchedulerSupport.NONE)
    public final Disposable subscribe(Consumer<? super T> onNext) {
        return subscribe(onNext, Functions.ON_ERROR_MISSING, Functions.EMPTY_ACTION, Functions.emptyConsumer());
    }
@ CheckReturnValue @ SchedulerSupport ( SchedulerSupport . NONE ) public final Disposable subscribe ( Consumer < ? super T > onNext ) { return subscribe ( onNext , Functions . ON_ERROR_MISSING , Functions . EMPTY_ACTION , Functions . emptyConsumer ( ) ) ; }
Subscribes to an ObservableSource and provides a callback to handle the items it emits.
<p>
If the Observable emits an error, it is wrapped into an
{@link io.reactivex.exceptions.OnErrorNotImplementedException OnErrorNotImplementedException}
and routed to the RxJavaPlugins.onError handler.
<dl>
<dt><b>Scheduler:</b></dt>
<dd>{@code subscribe} does not operate by default on a particular {@link Scheduler}.</dd>
</dl>

@param onNext
the {@code Consumer<T>} you have designed to accept emissions from the ObservableSource
@return a {@link Disposable} reference with which the caller can stop receiving items before
the ObservableSource has finished sending them
@throws NullPointerException
if {@code onNext} is null
@see <a href="http://reactivex.io/documentation/operators/subscribe.html">ReactiveX operators documentation: Subscribe</a>
Subscribes to an ObservableSource and provides a callback to handle the items it emits . <p > If the Observable emits an error it is wrapped into an { @link io . reactivex . exceptions . OnErrorNotImplementedException OnErrorNotImplementedException } and routed to the RxJavaPlugins . onError handler . <dl > <dt > <b > Scheduler : < / b > < / dt > <dd > { @code subscribe } does not operate by default on a particular { @link Scheduler } . < / dd > < / dl >