Skip to main content

Return to Question

Post Timeline

Notice removed Reward existing answer by Naman
Bounty Ended with Nicolai Parlog's answer chosen by Naman
Notice added Reward existing answer by Naman
Bounty Started worth 500 reputation by Naman
edited tags
Link
Naman
Naman
  • 32.8k
  • 32
  • 240
  • 385
Source Link
Nicolai Parlog
Nicolai Parlog
  • 51.7k
  • 25
  • 139
  • 262

How to solve InaccessibleObjectException ("Unable to make {member} accessible: module {A} does not 'opens {package}' to {B}") on Java 9?

This exception occurs in a wide variety of scenarios when running an application on Java 9. Certain libraries and frameworks (Spring, Hibernate, JAXB) are particularly prone to it. Here's an example from Javassist:

java.lang.reflect.InaccessibleObjectException: Unable to make protected final java.lang.Class java.lang.ClassLoader.defineClass(java.lang.String,byte[],int,int,java.security.ProtectionDomain) throws java.lang.ClassFormatError accessible: module java.base does not "opens java.lang" to unnamed module @1941a8ff
    at java.base/jdk.internal.reflect.Reflection.throwInaccessibleObjectException(Reflection.java:427)
    at java.base/java.lang.reflect.AccessibleObject.checkCanSetAccessible(AccessibleObject.java:201)
    at java.base/java.lang.reflect.Method.checkCanSetAccessible(Method.java:192)
    at java.base/java.lang.reflect.Method.setAccessible(Method.java:186)
    at javassist.util.proxy.SecurityActions.setAccessible(SecurityActions.java:102)
    at javassist.util.proxy.FactoryHelper.toClass2(FactoryHelper.java:180)
    at javassist.util.proxy.FactoryHelper.toClass(FactoryHelper.java:163)
    at javassist.util.proxy.ProxyFactory.createClass3(ProxyFactory.java:501)
    at javassist.util.proxy.ProxyFactory.createClass2(ProxyFactory.java:486)
    at javassist.util.proxy.ProxyFactory.createClass1(ProxyFactory.java:422)
    at javassist.util.proxy.ProxyFactory.createClass(ProxyFactory.java:394)

The message says:

Unable to make protected final java.lang.Class java.lang.ClassLoader.defineClass(java.lang.String,byte[],int,int,java.security.ProtectionDomain) throws java.lang.ClassFormatError accessible: module java.base does not "opens java.lang" to unnamed module @1941a8ff

What can be done to avoid the exception and have the program run successfully?