Is the skip() method a short circuiting-operation?

Melad Basilius :

I am reading about Java streams' short-circuiting operations and found in some articles that skip() is a short-circuiting operation.

In another article they didn't mention skip() as a short-circuiting operation.

Now I am confused; is skip() a short-circuiting operation or not?

Ousmane D. :

From the java doc under the "Stream operations and pipelines" section :

An intermediate operation is short-circuiting if, when presented with infinite input, it may produce a finite stream as a result. A terminal operation is short-circuiting if, when presented with infinite input, it may terminate in finite time.

Emphasis mine.

if you were to call skip on an infinite input it won't produce a finite stream hence not a short-circuiting operation.

The only short-circuiting intermediate operation in JDK8 is limit as it allows computations on infinite streams to complete in finite time.

Example:

if you were to execute this program with the use of skip:

String[] skip = Stream.generate(() -> "test") // returns an infinite stream
                      .skip(20) 
                      .toArray(String[]::new);

it will not produce a finite stream hence you would eventually end up with something along the lines of "java.lang.OutOfMemoryError: Java heap space".

whereas if you were to execute this program with the use of limit, it will cause the computation to finish in a finite time:

String[] limit = Stream.generate(() -> "test") // returns an infinite stream
                       .limit(20)
                       .toArray(String[]::new);