Environment Information
JRuby: 10.0.3.0
Java:
openjdk 25.0.2 2026-01-20
OpenJDK Runtime Environment (build 25.0.2+10-Ubuntu-124.04)
OpenJDK 64-Bit Server VM (build 25.0.2+10-Ubuntu-124.04, mixed mode, sharing)
OS: Ubuntu 24.04.3 LTS
Steps to reproduce
Java code (JavaFXMain.java):
public class JavaFXMain extends javafx.application.Application {
public void start(javafx.stage.Stage stage)
{
new org.jruby.embed.ScriptingContainer().runScriptlet("load 'JavaFX.rb'");
}
}Ruby code (JavaFX.rb):
Thread.abort_on_exception = true
class Timer < javafx.animation.AnimationTimer
def initialize
@lock = Mutex.new
start
end
def handle(time)
begin
while true
@lock.synchronize do
end
end
rescue
puts $!
puts $!.backtrace
end
end
end
Timer.new
Thread.new do
sleep 3
raise
endCompile:
javac --module-path /usr/share/openjfx/lib --add-modules javafx.controls -cp ./jruby-complete.jar JavaFXMain.java
Run:
java --module-path /usr/share/openjfx/lib --add-modules javafx.controls -cp ./jruby-complete.jar:. JavaFXMain
Expected Behavior
No deadlock occurs.
Actual Behavior
After a few seconds, the following error appears
deadlock; lock already owned by another fiber belonging to the same thread
org/jruby/ext/thread/Mutex.java:110:in 'lock'
org/jruby/ext/thread/Mutex.java:192:in 'synchronize'
JavaFX.rb:12:in 'handle'
Environment Information
JRuby: 10.0.3.0
Java:
openjdk 25.0.2 2026-01-20
OpenJDK Runtime Environment (build 25.0.2+10-Ubuntu-124.04)
OpenJDK 64-Bit Server VM (build 25.0.2+10-Ubuntu-124.04, mixed mode, sharing)
OS: Ubuntu 24.04.3 LTS
Steps to reproduce
Java code (JavaFXMain.java):
Ruby code (JavaFX.rb):
Compile:
Run:
Expected Behavior
No deadlock occurs.
Actual Behavior
After a few seconds, the following error appears