src/main/java/io/reactivex/Single.java
@CheckReturnValue
    @SchedulerSupport(SchedulerSupport.NONE)
    @SuppressWarnings("unchecked")
    public static <T> Single<T> never() {
        return RxJavaPlugins.onAssembly((Single<T>) SingleNever.INSTANCE);
    }
@CheckReturnValue
    @SchedulerSupport(SchedulerSupport.NONE)
    @SuppressWarnings("unchecked")
    public static <T> Single<T> never() {
        return RxJavaPlugins.onAssembly((Single<T>) SingleNever.INSTANCE);
    }
@ CheckReturnValue @ SchedulerSupport ( SchedulerSupport . NONE ) @ SuppressWarnings ( "unchecked" ) public static < T > Single < T > never ( ) { return RxJavaPlugins . onAssembly ( ( Single < T > ) SingleNever . INSTANCE ) ; }
Returns a singleton instance of a never-signalling Single (only calls onSubscribe).
<p>
<img width="640" height="244" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.never.png" alt="">
<dl>
<dt><b>Scheduler:</b></dt>
<dd>{@code never} does not operate by default on a particular {@link Scheduler}.</dd>
</dl>
@param <T> the target value type
@return the singleton never instance
@since 2.0
Returns a singleton instance of a never - signalling Single ( only calls onSubscribe ) . <p > <img width = 640 height = 244 src = https : // raw . github . com / wiki / ReactiveX / RxJava / images / rx - operators / Single . never . png alt = > <dl > <dt > <b > Scheduler : < / b > < / dt > <dd > {