Stream.toList vs Collectors.toList: Which Java List Conversion Is Faster?

Previously introduced Java 16 Stream enhancements, including direct toList() conversion.

The common ways to convert a Stream to a List are:

list.stream().toList();
list.stream().collect(Collectors.toList());
list.stream().collect(Collectors.toUnmodifiableList());

Readers often ask about the difference between Stream.toList() and Collectors.toList() and their performance. Stream.toList() returns an immutable list. Collectors.toList() returns a mutable list. Collectors.toUnmodifiableList() also returns an immutable list.

We benchmarked the three methods using JMH.

@BenchmarkMode(Mode.All)
@Fork(1)
@State(Scope.Thread)
@Warmup(iterations = 20, time = 1, batchSize = 10000)
@Measurement(iterations = 20, time = 1, batchSize = 10000)
public class BenchmarkStreamToList {
    @Benchmark
    public List<Integer> streamToList() {
        return IntStream.range(1, 1000).boxed().toList();
    }
    @Benchmark
    public List<Integer> collectorsToList() {
        return IntStream.range(1, 1000).boxed().collect(Collectors.toList());
    }
    @Benchmark
    public List<Integer> collectorsToUnmodifiableList() {
        return IntStream.range(1, 1000).boxed().collect(Collectors.toUnmodifiableList());
    }
}

The benchmark results show that streamToList outperforms both collector variants in throughput, average latency, and tail‑latency metrics, even when the element count is increased to 10,000.

Conclusion: Stream.toList() provides better overall performance compared to Collectors.toList() and Collectors.toUnmodifiableList().