Hi Razvan,
I don't know Clojure but if this happens during compilation of Clojure
source(s) (in clojure.lang.Compile), then the question is: Does Clojure
compiler really need to execute static initializers of classes it is
"resolving"? It seems it needs to load the classes (presumably because
it is using Java reflection to introspect them), but does it really need
to initialize the classes?
If it only needs to introspect the classes (but not execute constructors
or methods in them or access fields), then it should be using the 3-arg
Class.forName() method:
public static Class<?> forName(String name, boolean initialize,
ClassLoader loader)
...passing 'false' as the 2nd argument. That way the "resolved" classes
would be loaded but not initialized. Clojure compiler could still
introspect them, but no code in classes would be executed. This would be
much safer.
Regards, Peter
On 3/24/19 3:16 PM, Răzvan Rotaru wrote:
Hi,
I am trying to use OpenJFX 11.0.2 (for Linux) with Clojure and
https://github.com/fn-fx/fn-fx, and stumbled upon a problem for which I
would like to ask for advice here. The Problem occurs during compilation of
some clojure code, which triggers class loading for javafx.stage.Screen,
which fails with following stack trace (only the relevant part):
java.lang.IllegalStateException: This operation is permitted on the event
thread only; currentThread = main
at com.sun.glass.ui.Application.checkEventThread(Application.java:441)
at com.sun.glass.ui.Screen.setEventHandler(Screen.java:369)
at
com.sun.javafx.tk.quantum.QuantumToolkit.setScreenConfigurationListener(QuantumToolkit.java:684)
at javafx.stage.Screen.<clinit>(Screen.java:74)
at java.base/java.lang.Class.forName0(Native Method)
at java.base/java.lang.Class.forName(Class.java:398)
at clojure.lang.RT.classForName(RT.java:2207)
at clojure.lang.RT.classForName(RT.java:2216)
at clojure.lang.Compiler.resolveIn(Compiler.java:7394)
at clojure.lang.Compiler.resolve(Compiler.java:7357)
at clojure.lang.Compiler.analyzeSymbol(Compiler.java:7318)
at clojure.lang.Compiler.analyze(Compiler.java:6768)
at clojure.lang.Compiler.analyze(Compiler.java:6745)
at clojure.lang.Compiler$InvokeExpr.parse(Compiler.java:3888)
Being only compilation, there should be no Toolkit initialisation, hence no
event thread. Looking at the code it seems that the Screen class can only
be loaded from the event thread. Is this a bug or the intended behaviour?
Is there a way around this for my use case? How does OpenJFX ensure that
Screen is always loaded on the correct thread?
Related bug in fn-fx: https://github.com/fn-fx/fn-fx/issues/25
Cheers,
Răzvan
