Java: What is the difference between Stream.skip() and Stream.dropWhile()?

skip(n) — discards exactly n elements. dropWhile(predicate) — discards elements while a condition is true. Think of skip() as fast-forwarding exactly 5 minutes, while dropWhile() as fast-forwarding until you reach a scene you want to watch.

skip():

• Skips exactly n elements.
• Static count.
• Works on any stream.

1List<Integer> result = List.of(1,2,3,4,5).stream()
2    .skip(2)
3    .toList();
4// [3, 4, 5]

dropWhile():

• Drops while predicate is true.
• Dynamic count.
• Stops dropping at first false.

1List<Integer> result = List.of(1,2,3,4,5).stream()
2    .dropWhile(x -> x < 3)
3    .toList();
4// [3, 4, 5]

Key difference:

• skip() — count-based, static, works on any stream.
• dropWhile() — condition-based, dynamic, best on sorted streams.

1// Real-world: skip to page 3 (skip 20 items)
2list.stream().skip(20).limit(10).collect(toList());
3
4// Real-world: drop entries before a cutoff
5logEntries.stream()
6    .sorted(Comparator.comparing(LogEntry::getTimestamp))
7    .dropWhile(e -> e.getTimestamp().isBefore(cutoff))
8    .collect(toList());