ci: docker cmake java error

[Mizux]

So CI build jobs fail while other pass -> need to investigate...

OS	JVM	MVN	TEST
almalinux	openjdk 21	3.9.9	OK
alpine	openjdk 21	3.9.14	OK
archlinux	openjdk 26	3.9.13	NOK
debian	openjdk 21	3.9.9	OK
fedora	openjdk 25	3.9.11	NOK
opensuse	openjdk 21	3.9.14	NOK
rockylinux	openjdk 21	3.9.9	OK
ubuntu	openjdk 21	3.9.9	OK

ref: https://github.com/google/or-tools/actions/runs/23857346636

[Mizux]

on my archlinux:

$ cmake -S. -Bbuild_java -DBUILD_JAVA=ON
$ cmake --build build_java --config Release -j 12
$ ldd build_java/lib/libjniortools.so | grep "not found"                                   
	libjawt.so => not found
	libjvm.so => not found
$ (cd build_java && ctest -C Release -R "java_graph_FlowTest.*$")
...
[ERROR] Tests run: 2, Failures: 0, Errors: 2, Skipped: 0, Time elapsed: 0.703 s <<< FAILURE! -- in com.google.ortools.graph.FlowTest
[ERROR] com.google.ortools.graph.FlowTest.testMinCostFlow -- Time elapsed: 0.380 s <<< ERROR!
java.lang.UnsatisfiedLinkError: 'long com.google.ortools.graph.mainJNI.new_MinCostFlow__SWIG_2()'
	at com.google.ortools.graph.mainJNI.new_MinCostFlow__SWIG_2(Native Method)
	at com.google.ortools.graph.MinCostFlow.<init>(MinCostFlow.java:60)
	at com.google.ortools.graph.FlowTest.testMinCostFlow(FlowTest.java:37)
	at java.base/java.lang.reflect.Method.invoke(Method.java:580)
	at java.base/java.util.ArrayList.forEach(ArrayList.java:1596)
	at java.base/java.util.ArrayList.forEach(ArrayList.java:1596)

[ERROR] com.google.ortools.graph.FlowTest.testMaxFlow -- Time elapsed: 0.305 s <<< ERROR!
java.lang.UnsatisfiedLinkError: 'long com.google.ortools.graph.mainJNI.new_MaxFlow()'
	at com.google.ortools.graph.mainJNI.new_MaxFlow(Native Method)
	at com.google.ortools.graph.MaxFlow.<init>(MaxFlow.java:52)
	at com.google.ortools.graph.FlowTest.testMaxFlow(FlowTest.java:67)
	at java.base/java.lang.reflect.Method.invoke(Method.java:580)
	at java.base/java.util.ArrayList.forEach(ArrayList.java:1596)
	at java.base/java.util.ArrayList.forEach(ArrayList.java:1596)

[INFO] 
[INFO] Results:
[INFO] 
[ERROR] Errors: 
[ERROR]   FlowTest.testMaxFlow:67 » UnsatisfiedLink 'long com.google.ortools.graph.mainJNI.new_MaxFlow()'
[ERROR]   FlowTest.testMinCostFlow:37 » UnsatisfiedLink 'long com.google.ortools.graph.mainJNI.new_MinCostFlow__SWIG_2()'
[INFO] 
[ERROR] Tests run: 2, Failures: 0, Errors: 2, Skipped: 0
....
The following tests FAILED:
	199 - java_graph_FlowTest (Failed)

Then trying to locate libjvm.so

$ pacman -Qo /usr/lib/jvm/java-26-openjdk/lib/server/libjvm.so
/usr/lib/jvm/java-26-openjdk/lib/server/libjvm.so is owned by jdk-openjdk 26.u35-1

$ export LD_LIBRARY_PATH=/usr/lib/jvm/java-26-openjdk/lib/server
$ (cd build_java && ctest -C Release -R "java_graph_FlowTest.*$")
Test project /home/mizux/work/main/build_java
    Start 199: java_graph_FlowTest
1/1 Test #199: java_graph_FlowTest ..............   Passed    3.27 sec
100% tests passed, 0 tests failed out of 1
Total Test time (real) =   3.28 sec

according to https://cmake.org/cmake/help/latest/module/FindJNI.html we have

JNI::JVM
Added in version 3.24.
Target encapsulating the Java Virtual Machine (JVM) library usage requirements, available if component JVM is found.
note: Currently we are only using JNI::JNI to get jni.h ...

dev note:

$ comm -23 <(nm -u -C build_java/lib/libjniortools.so | awk '{print $NF}' | sort -u) \
         <(nm -C -D --defined-only build_java/lib/libortools.so | awk '{print $NF}' | sort -u) | grep JNI
JNI_GetCreatedJavaVMs@SUNWprivate_1.1