为什么 Java.exe 突然无法找到文件/模块，即使 Windows Explorer 显示它们存在

Question

We're experiencing a strange issue - has anybody seen anything similar?

We have a Java/JavaFX desktop application that has been running successfully on a Windows platform (Server 2012) for almost a year.

Recently we moved the application to a different Windows platform (Server 2019, virtual machine).

The app is installed on a shared drive and is started several times a day. It initially runs successfully but at some point in the day will no longer start.

The command line is:

java -p WolfToolkit.jar;WolfToolkit_mods -m com.mycompany.wolftoolkit/com.mycompany.start.StartGUI

WolfToolkit_mods is a folder containing jars for the required modules. When the start-up error occurs, Java.exe reports thatvarying required modules cannot be found. After a lot of diagnostic testing, it appears that Java.exe can no longer detect any of the jar files in the WolfToolkit_mods folder even though Windows Explorer shows the correct content.

If I copy folder WolfToolkit_mods to WolfToolkit_mods2 and change the command to

java -p WolfToolkit.jar;WolfToolkit_mods2...

then the app starts correctly.

If I re-copy just one of the jar files into WolfToolkit_mods and use the original command, then only that file is visible. If all files are re-copied then the app runs correctly.

So, the behaviour is as if Java suddenly views WolfToolkit_mods as being empty and only detects each jar file when it is copied back in. Meanwhile Windows sees no problems. I should also mention that on rare occasions Java.exe suddenly starts reporting that WolfToolkit.jar is "Module format not recognized". Again, re-copying the file resolves the issue.

Any ideas on what this could be or how to diagnose? Thanks.

Windows Server 2019 Standard v10.0

JVM: OpenJDK 64-bit Server v11.0.10+9

Answer 1

This looks to have been caused by the virus checker which was quarantining all.jar files as "suspicious". Presumably when java.exe was trying to read the files on the module path the virus checking software intervened and the effect was that java.exe couldn't locate module-info and so reported missing modules.

Thanks to those who took the time to respond.