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java module access issue: "Class in a module cannot access class in unnamed module because module x does not read unnamed module y"

My source code compiles on java 7 and runs on java 11.
I am trying to integrate imperva RASP as a java agent in tomcat. However, when I start the tomcat server, it is throwing following exception:
Caused by: java.lang.IllegalAccessError: class sun.security.ec.ECDSASignature (in module jdk.crypto.ec) cannot access class com.imperva.rasp.AgentBridge (in unnamed module #0x66c61024) because module jdk.crypto.ec does not read unnamed module #0x66c61024
at jdk.crypto.ec/sun.security.ec.ECDSASignature.<init>(ECDSASignature.java:118)
at jdk.crypto.ec/sun.security.ec.ECDSASignature.<init>(ECDSASignature.java:106)
at jdk.crypto.ec/sun.security.ec.ECDSASignature$SHA1.<init>(ECDSASignature.java:214)
at jdk.crypto.ec/sun.security.ec.SunEC$ProviderService.newInstance(SunEC.java:102)
at java.base/java.security.Signature.isSpi(Signature.java:331)
The way I am passing java agent is:
JAVA_OPTS="-javaagent:$IMPERVA_JAR $JAVA_OPTS"
I went through multiple posts such as this one about --add-opens argument. Based on that, I am passing JDK_JAVA_OPTIONS="$JDK_JAVA_OPTIONS --add-opens=jdk.crypto.ec/sun.security.ec=ALL-UNNAMED"
I can see following statement in the logs:
Picked up JDK_JAVA_OPTIONS: --add-opens=jdk.crypto.ec/sun.security.ec=ALL-UNNAMED
Am I missing something here or is there any syntax error in the arguments that I am passing?
There is no any other configuration is done.
Any help is appreciated. Thank you.

Managed to solve it by using --add-reads instead of --add-opens.
JDK_JAVA_OPTIONS="$JDK_JAVA_OPTIONS --add-reads jdk.crypto.ec=ALL-UNNAMED"

Unable to run Flutter code in Android Studio?

I get an error everytime I try to run the default code that flutter provides for a new project
> java.lang.IllegalAccessError: class org.gradle.internal.compiler.java.ClassNameCollector (in unnamed module #0x1da59d23) cannot access class com.sun.tools.javac.code.Symbol$TypeSymbol (in module jdk.compiler) because module jdk.compiler does not export com.sun.tools.javac.code to unnamed module #0x1da59d23```
Any tips?
https://imgur.com/a/v97fcCz (I have run flutter doctor and this is the result after fixing the licenses)

Cannot run a HelloWorld on Intellij Idea (java.lang.IllegalAccessError)

I wanted to just run HelloWorld on Intellij Idea which is failed.
Java Version is "9-ea" in my macOS.
Error:Internal error: (java.lang.IllegalAccessError) class com.intellij.util.io.FileChannelUtil (in unnamed module #0x6ecc4cd7) cannot access class sun.nio.ch.FileChannelImpl (in module java.base) because module java.base does not export sun.nio.ch to unnamed module #0x6ecc4cd7
java.lang.IllegalAccessError: class com.intellij.util.io.FileChannelUtil (in unnamed module #0x6ecc4cd7) cannot access class sun.nio.ch.FileChannelImpl (in module java.base) because module java.base does not export sun.nio.ch to unnamed module #0x6ecc4cd7
at com.intellij.util.io.FileChannelUtil.setupUnInterruptibleHandle(FileChannelUtil.java:26)
......

Please make sure to use the release JDK version, not ea and update to the latest IntelliJ IDEA version.

I had the same error and the solution I've found was to downgrade my Java version (JDK) from 16 to 11. Then, it worked :)

What module is the unnamed package part of in Java?

I think that the unnamed package is part of the unnamed module, however I can't be sure as I can't find any answers online, so I posted my question here.
From https://docs.oracle.com/javase/tutorial/java/package/createpkgs.html:
If you do not use a package statement, your type ends up in an unnamed package. Generally speaking, an unnamed package is only for small or temporary applications or when you are just beginning the development process. Otherwise, classes and interfaces belong in named packages.
*Edit: The answer is that the unnamed package is part of the unnamed module

It is in a (the) unnamed module.
According to the Java 11 edition of the JLS 7.4.2
The host system must associate ordinary compilation units in an unnamed package with an unnamed module (§7.7.5), not a named module.
This is more authoritative than the Java Tutorial.

Method getModule returning unnamed module for class in named module

I just started to have a look at the Java 9 module system and I was wondering whether it is possible for a class to know in which module it is located.
Therefor I created the following module
module de.test {
exports de.test.myexport;
}
and compiled a jar file that looks like
> jar --print-module-descriptor --file=Java9Test-1.0-SNAPSHOT.jar
de.test
requires mandated java.base
exports de.test.myexport
In package de.test, I have a class called Overview where I'm calling
Module module = Overview.class.getModule();
However, the returned module object is unnamed and has no ModuleDescriptor.
Am I using getModule() correctly here, or is there any other way to load the module of a class?
I'm using JDK 9 build 120 on OS X.

All JARs on the class path (with java --class-path ...) get bundled into the same so-called unnamed module, regardless of whether they are "a real module" or "just a JAR". When you ask a class from such a JAR for its module, you get the result you describe.
Try putting the JAR on the module path (with java --module-path ...) and Class::getModule should return what you expect.