Create stream from iterable in java 8

gistfile1.java

public class StreamUtil<T>{
    public static <T> Stream<T> ofIterable(Iterable<T> iter){
        Iterator<T> iterator = iter.iterator();
        
        Stream.Builder<T> builder = Stream.builder();

        while(iterator.hasNext()){
            builder.add(iterator.next());
        }

        return builder.build();
    }
}

// usage

import java.util.List;
import java.util.concurrent.ExecutionException;

import static java.util.Arrays.asList;

public class Main{
    public static void main(String[] arsg) throws InterruptedException, ExecutionException {
       
        List<String> strings = asList("oooo", "ba", "baz", "booo");

        System.out.println(StreamUtil.ofIterable(strings).count());
    }

}

Don't do this. See https://docs.oracle.com/javase/8/docs/api/java/util/stream/StreamSupport.html , which converts a Spliterator. Iterable (now) has a default method spliterator, so all you need is StreamSupport.stream(iterable.spliterator()). In addition, this technique is lazy, whereas populating a builder requires walking the full Iterable.