Uploaded image for project: 'JDK'
  1. JDK
  2. JDK-8273656

Improve java.lang.invoke.MethodType.parameterList() and its usage

    XMLWordPrintable

    Details

    • Type: Enhancement
    • Status: Resolved
    • Priority: P4
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: 18
    • Component/s: core-libs
    • Labels:
      None

      Description

      Currently the method is implemented like

      public List<Class<?>> parameterList() {
        return Collections.unmodifiableList(Arrays.asList(ptypes.clone()));
      }

      This seems to be excessive, as three objects are allocated here. Instead we can use List.of(ptypes) which doesn't allocate anything for empty array and for one of length 1 and 2 allocates lightweight objects with 1 and two fields respectively still copying longer arrays. This is likely to be fruitful as most of methods have 0-2 parameters.

      Also there is a couple of cases when MethodType.parameterLis() is called to get its size, which is excessive either as we can use MethodType.parameterCount() instead.

        Attachments

          Issue Links

            Activity

              People

              Assignee:
              stsypanov Sergey Tsypanov
              Reporter:
              stsypanov Sergey Tsypanov
              Votes:
              0 Vote for this issue
              Watchers:
              4 Start watching this issue

                Dates

                Created:
                Updated:
                Resolved: