java8-peek print value in proccessing

Use java8-api Refactor-Testing-Debugging

Examining values flowing in a stream pipeline with peek

 

Use peek to print the intermediate value before and after each operation in the stream pipeline

@Test
public void tset(){
    List<Integer> numbvers= Arrays.asList(2,3,4,5,6);

    List<Integer> result=numbvers.stream().peek(x-> System.out.println("from stream:" +x))
            .map(x->x+1).peek(x-> System.out.println("after map:"+x)).filter(x->x%2==0)
            .peek(x-> System.out.println("after filter:"+x))
            .limit(3)
            .peek(x-> System.out.println("after limit:"+x))
            .collect(Collectors.toList());
}