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  1. JDK
  2. JDK-8233837

getConstructor() not working as expected

    Details

    • Type: Bug
    • Status: Open
    • Priority: P4
    • Resolution: Unresolved
    • Affects Version/s: 11
    • Fix Version/s: None
    • Component/s: core-libs
    • Labels:

      Description

      ADDITIONAL SYSTEM INFORMATION :
      Windows 10, OpenJDK 11.0.2


      A DESCRIPTION OF THE PROBLEM :
      getConstructor() throws 'NoSuchMethodException <init>()' with default inner and outer and also private inner classes with default-constructors.
      These classes can be instantiated by normal new aswell with the depracted Class#newInstance() method but not with Class#getConstructor#newInstance().


      STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
      to test you can use the provides sourcecode


      EXPECTED VERSUS ACTUAL BEHAVIOR :
      EXPECTED -
      all of the examples should work without error

      ACTUAL -
      --- ni.problem.NewInstanceProblem$PublicInnerClass
        -> normal instantiation -> created
        -> Class.forName()
        -> newInstance() -> created
        -> getConstructor() -> newInstance() -> created
      --- ni.problem.NewInstanceProblem$DefaultInnerClass
        -> normal instantiation -> created
        -> Class.forName()
        -> newInstance() -> created
        -> getConstructor()
      java.lang.NoSuchMethodException: ni.problem.NewInstanceProblem$DefaultInnerClass.<init>()
              at java.base/java.lang.Class.getConstructor0(Class.java:3350)
              at java.base/java.lang.Class.getConstructor(Class.java:2152)
              at ni.problem.NewInstanceProblem.create(NewInstanceProblem.java:47)
              at ni.problem.NewInstanceProblem.main(NewInstanceProblem.java:65)
      --- ni.problem.NewInstanceProblem$PrivateInnerClass
        -> normal instantiation -> created
        -> Class.forName()
        -> newInstance() -> created
        -> getConstructor()
      java.lang.NoSuchMethodException: ni.problem.NewInstanceProblem$PrivateInnerClass.<init>()
              at java.base/java.lang.Class.getConstructor0(Class.java:3350)
              at java.base/java.lang.Class.getConstructor(Class.java:2152)
              at ni.problem.NewInstanceProblem.create(NewInstanceProblem.java:47)
              at ni.problem.NewInstanceProblem.main(NewInstanceProblem.java:67)
      --- ni.problem.PublicOuterClass
        -> normal instantiation -> created
        -> Class.forName()
        -> newInstance() -> created
        -> getConstructor() -> newInstance() -> created
      --- ni.problem.DefaultOuterClass
        -> normal instantiation -> created
        -> Class.forName()
        -> newInstance() -> created
        -> getConstructor()
      java.lang.NoSuchMethodException: ni.problem.DefaultOuterClass.<init>()
              at java.base/java.lang.Class.getConstructor0(Class.java:3350)
              at java.base/java.lang.Class.getConstructor(Class.java:2152)
              at ni.problem.NewInstanceProblem.create(NewInstanceProblem.java:47)
              at ni.problem.NewInstanceProblem.main(NewInstanceProblem.java:70)



      ---------- BEGIN SOURCE ----------
      --- source for NewInstanceProblem:
      package ni.problem;

      import java.lang.reflect.Constructor;
      import java.util.function.Supplier;

      public class NewInstanceProblem {

        public static class PublicInnerClass {
          //
        }

        static class DefaultInnerClass {
          //
        }

        private static class PrivateInnerClass {
          //
        }

        private static void create(final String clazzName,
          final Supplier<Object> doNew) {

          System.out.printf("--- %s%n", clazzName);

          try {
            System.out.printf(" -> normal instantiation", clazzName);
            doNew.get();
            System.out.printf(" -> created%n");
          } catch (final Exception e) {
            System.out.printf("%n");
            e.printStackTrace(System.out);
          }

          try {
            System.out.printf(" -> Class.forName()%n", clazzName);
            final Class<?> c = Class.forName(clazzName);
            try {
              System.out.printf(" -> newInstance()", clazzName);
              c.newInstance();
              System.out.printf(" -> created%n");
            } catch (final Exception e) {
              System.out.printf("%n");
              e.printStackTrace(System.out);
            }
            try {
              System.out.printf(" -> getConstructor()", clazzName);
              final Constructor<?> cx = c.getConstructor();
              System.out.printf(" -> newInstance()", clazzName);
              final Object o = cx.newInstance();
              System.out.printf(" -> created%n");
            } catch (final Exception e) {
              System.out.printf("%n");
              e.printStackTrace(System.out);
            }
          } catch (final Exception e) {
            System.out.printf("%n");
            e.printStackTrace(System.out);
          }

        }

        public static void main(final String[] args) {
          create("ni.problem.NewInstanceProblem$PublicInnerClass",
            () -> new PublicInnerClass());
          create("ni.problem.NewInstanceProblem$DefaultInnerClass",
            () -> new DefaultInnerClass());
          create("ni.problem.NewInstanceProblem$PrivateInnerClass",
            () -> new PrivateInnerClass());
          create("ni.problem.PublicOuterClass", () -> new PublicOuterClass());
          create("ni.problem.DefaultOuterClass", () -> new DefaultOuterClass());
        }

      }

      --- source for PublicOuterClass:
      package ni.problem;

      public class PublicOuterClass {
        //
      }

      --- source for DefaultOuterClass:
      package ni.problem;

      class DefaultOuterClass {
        //
      }


      ---------- END SOURCE ----------

      CUSTOMER SUBMITTED WORKAROUND :
      use deprecated newInstance() instead of recommended getConstructor().newInstance()


      FREQUENCY : always


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              • Assignee:
                darcy Joe Darcy
                Reporter:
                webbuggrp Webbug Group
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                • Created:
                  Updated: