Instead of allocating a copy of underlying array via `CharArrayWriter.toCharArray()` and passing it to constructor of String String str = new String(charArrayWriter.toCharArray()); we could call `toString()` method String str = charArrayWriter.toString(); decoding existing char[] without making a copy. This slightly speeds up the method reducing at the same time memory consumption for decoding URLs with non-latin symbols: @State(Scope.Thread) @BenchmarkMode(Mode.AverageTime) @OutputTimeUnit(TimeUnit.NANOSECONDS) @Fork(jvmArgsAppend = {"-Xms2g", "-Xmx2g"}) public class UrlEncoderBenchmark { private static final Charset charset = Charset.defaultCharset(); private static final String utf8Url = "https://ru.wikipedia.org/wiki/Организация_Объединённых_Наций"; // UN
@Benchmark public String encodeUtf8() { return URLEncoder.encode(utf8Url, charset); } } The benchmark on my maching give the following output: before Benchmark Mode Cnt Score Error Units UrlEncoderBenchmark.encodeUtf8 avgt 100 1166.378 ± 8.411 ns/op UrlEncoderBenchmark.encodeUtf8:·gc.alloc.rate avgt 100 932.944 ± 6.393 MB/sec UrlEncoderBenchmark.encodeUtf8:·gc.alloc.rate.norm avgt 100 1712.193 ± 0.005 B/op UrlEncoderBenchmark.encodeUtf8:·gc.churn.G1_Eden_Space avgt 100 929.221 ± 24.268 MB/sec UrlEncoderBenchmark.encodeUtf8:·gc.churn.G1_Eden_Space.norm avgt 100 1705.444 ± 43.235 B/op UrlEncoderBenchmark.encodeUtf8:·gc.churn.G1_Survivor_Space avgt 100 0.006 ± 0.001 MB/sec UrlEncoderBenchmark.encodeUtf8:·gc.churn.G1_Survivor_Space.norm avgt 100 0.011 ± 0.002 B/op UrlEncoderBenchmark.encodeUtf8:·gc.count avgt 100 652.000 counts UrlEncoderBenchmark.encodeUtf8:·gc.time avgt 100 334.000 ms after Benchmark Mode Cnt Score Error Units UrlEncoderBenchmark.encodeUtf8 avgt 100 1058.851 ± 6.006 ns/op UrlEncoderBenchmark.encodeUtf8:·gc.alloc.rate avgt 100 931.489 ± 5.182 MB/sec UrlEncoderBenchmark.encodeUtf8:·gc.alloc.rate.norm avgt 100 1552.176 ± 0.005 B/op UrlEncoderBenchmark.encodeUtf8:·gc.churn.G1_Eden_Space avgt 100 933.491 ± 24.164 MB/sec UrlEncoderBenchmark.encodeUtf8:·gc.churn.G1_Eden_Space.norm avgt 100 1555.488 ± 39.204 B/op UrlEncoderBenchmark.encodeUtf8:·gc.churn.G1_Survivor_Space avgt 100 0.006 ± 0.001 MB/sec UrlEncoderBenchmark.encodeUtf8:·gc.churn.G1_Survivor_Space.norm avgt 100 0.010 ± 0.002 B/op UrlEncoderBenchmark.encodeUtf8:·gc.count avgt 100 655.000 counts UrlEncoderBenchmark.encodeUtf8:·gc.time avgt 100 333.000 ms ------------- Commit messages: - Merge branch 'master' into enc - Improve URLEncoder.encode(String, Charset) Changes: https://git.openjdk.java.net/jdk/pull/1598/files Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=1598&range=00 Issue: https://bugs.openjdk.java.net/browse/JDK-8259699 Stats: 8 lines in 1 file changed: 0 ins; 0 del; 8 mod Patch: https://git.openjdk.java.net/jdk/pull/1598.diff Fetch: git fetch https://git.openjdk.java.net/jdk pull/1598/head:pull/1598 PR: https://git.openjdk.java.net/jdk/pull/1598