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  1. JDK
  2. JDK-8222955

Optimize String.replace(CharSequence, CharSequence) for common cases

    Details

    • Type: Enhancement
    • Status: Resolved
    • Priority: P4
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: 13
    • Component/s: core-libs
    • Labels:
      None
    • Subcomponent:
    • Resolved In Build:
      b20

      Description

      Adding special handling of the case when this String and both arguments are Latin1 encoded shows significant performance improvement.

      With the benchmark
      public class StringReplace {
          public String s = new String("java.lang.String");
          @Benchmark
          public String replace1_0() {
              return s.replace(".", "");
          }
          @Benchmark
          public String replace1_1() {
              return s.replace(".", "/");
          }
          @Benchmark
          public String replace1_2() {
              return s.replace(".", "::");
          }
      }

      the following numbers are observed:
      prior fix:
      Benchmark Mode Cnt Score Error Units
      StringReplace.replace1_0 avgt 18 76.706 ± 2.124 ns/op
      StringReplace.replace1_1 avgt 18 90.630 ± 4.680 ns/op
      StringReplace.replace1_2 avgt 18 110.723 ± 12.093 ns/op

      after fix:
      Benchmark Mode Cnt Score Error Units
      StringReplace.replace1_0 avgt 18 53.609 ± 0.478 ns/op
      StringReplace.replace1_1 avgt 18 24.170 ± 0.214 ns/op
      StringReplace.replace1_2 avgt 18 63.632 ± 0.648 ns/op

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              • Assignee:
                igerasim Ivan Gerasimov
                Reporter:
                igerasim Ivan Gerasimov
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                Dates

                • Created:
                  Updated:
                  Resolved: