Develop Reference

OpenJDK11 java.lang.ClassCastException

java.lang.ClassCastException: class sun.font.CompositeFont cannot be cast to class sun.font.PhysicalFont (sun.font.CompositeFont and sun.font.PhysicalFont are in module java.desktop of loader 'bootstrap')
java.desktop/sun.font.SunFontManager.getDefaultPhysicalFont(SunFontManager.java:1086)
java.desktop/sun.font.SunFontManager.initialiseDeferredFont(SunFontManager.java:965)
java.desktop/sun.font.SunFontManager.initialiseDeferredFonts(SunFontManager.java:831)
java.desktop/sun.font.SunFontManager.loadFonts(SunFontManager.java:3182)
java.desktop/sun.awt.X11FontManager.loadFonts(X11FontManager.java:438)
java.desktop/sun.font.SunFontManager.getAllInstalledFonts(SunFontManager.java:3543)
java.desktop/sun.java2d.SunGraphicsEnvironment.getAllFonts(SunGraphicsEnvironment.java:209)
java.desktop/sun.java2d.HeadlessGraphicsEnvironment.getAllFonts(HeadlessGraphicsEnvironment.java:72)
I have openjdk11 in my Centos server. I have seen this issue fixed by installing fontconfig package in os. Is there a way that i can fix this issue without installing any package?
I tried to copy some the fontconfig.properties files in my $JAVA_HOME/lib/ folder

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"

Is there a way to solve this internal error in Intellij

I just wrote a simple hello world program in Intellij and this is the output when I tried to run the program.
Error:Internal error: (java.lang.IllegalAccessError) class com.intellij.util.io.FileChannelUtil (in unnamed module #0x306279ee) cannot access class sun.nio.ch.FileChannelImpl (in module java.base) because module java.base does not export sun.nio.ch to unnamed module #0x306279ee

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)

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.