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  1. JDK
  2. JDK-8223014

Calling java.lang.Class.newInstance from JNI Invocation API causes NPE

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      Description

      A DESCRIPTION OF THE PROBLEM :
      I can reproduce this with the OpenJDK 12 RPMs on Fedora 30, but from looking at <https://hg.openjdk.java.net/jdk/jdk12/file/06222165c35f/src/java.base/share/classes/java/lang/Class.java> it looks plausible that it is a common issue that Reflection.getCallerClass() returns null when java.lang.Class.newInstance is called from the JNI Invocation API, and that null is propagated to jdk.internal.reflect.Reflection.verifyMemberAccess as parameter currentClass, which dereferences it at <https://hg.openjdk.java.net/jdk/jdk12/file/06222165c35f/src/java.base/share/classes/jdk/internal/reflect/Reflection.java#l130>.
      This is known to have been working with older OpenJDK (at least 1.8).

      STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
      Compile the provided test.cc with `g++ -I/usr/lib/jvm/java-12-openjdk-12.0.0.33-1.ea.1.rolling.fc30.x86_64/include -I/usr/lib/jvm/java-12-openjdk-12.0.0.33-1.ea.1.rolling.fc30.x86_64/include/linux /usr/lib/jvm/java-12-openjdk-12.0.0.33-1.ea.1.rolling.fc30.x86_64/lib/server/libjvm.so test.cc` and run it with `LD_LIBRARY_PATH=/usr/lib/jvm/java-12-openjdk-12.0.0.33-1.ea.1.rolling.fc30.x86_64/lib/server ./a.out`.

      EXPECTED VERSUS ACTUAL BEHAVIOR :
      EXPECTED -
      exit 0
      ACTUAL -
      Exception in thread "main" java.lang.NullPointerException
      at java.base/jdk.internal.reflect.Reflection.verifyMemberAccess(Reflection.java:130)
      at java.base/java.lang.reflect.AccessibleObject.slowVerifyAccess(AccessibleObject.java:673)
      at java.base/java.lang.reflect.AccessibleObject.verifyAccess(AccessibleObject.java:666)
      at java.base/java.lang.reflect.AccessibleObject.checkAccess(AccessibleObject.java:638)
      at java.base/java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:490)
      at java.base/java.lang.reflect.ReflectAccess.newInstance(ReflectAccess.java:166)
      at java.base/jdk.internal.reflect.ReflectionFactory.newInstance(ReflectionFactory.java:404)
      at java.base/java.lang.Class.newInstance(Class.java:590)
      Aborted

      ---------- BEGIN SOURCE ----------
      #include <cstdlib>

      #include "jni.h"

      void handleError(JNIEnv * env) {
          if (env->ExceptionCheck()) {
              env->ExceptionDescribe();
              std::abort();
          }
      }

      int main() {
          JavaVM * vm;
          JNIEnv * env;
          JavaVMInitArgs args{JNI_VERSION_1_2, 0, nullptr, true};
          if (JNI_CreateJavaVM(&vm, reinterpret_cast<void **>(&env), &args) != JNI_OK) {
              std::abort();
          }
          auto const c1 = env->FindClass("java/lang/Class");
          handleError(env);
          auto const id = env->GetMethodID(c1, "newInstance", "()Ljava/lang/Object;");
          handleError(env);
          auto const c2 = env->FindClass("java/lang/Object");
          handleError(env);
          env->CallObjectMethod(c2, id);
          handleError(env);
      }
      ---------- END SOURCE ----------

      CUSTOMER SUBMITTED WORKAROUND :
      Call via JNI the suggested replacement of clazz.getDeclaredConstructor().newInstance() instead of the deprecated java.lang.Class.newInstance().

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              • Assignee:
                psonal Pallavi Sonal
                Reporter:
                webbuggrp Webbug Group
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                • Created:
                  Updated:
                  Resolved: