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NativeBinaryLoader.loadLibrary() fails silently if clean extraction fails #46
Description
try {
loader.loadLibrary(LoadingCriterion.CLEAN_EXTRACTION);
} catch (Exception exception) {
throw new IllegalStateException(
"Failed to load a native library!", exception);
}If none of the registered native libraries is loadable (for instance because the libraries with matching predicates are missing from the JAR) the code above does not throw an exception. The failure isn't discovered until the application tries to invoke a native method, at which time a UnsatisfiedLinkError is thrown.
I expected an exception to be thrown during loadLibrary(). Ideally diagnostics should indicate:
- which libraries it tried to extract and load
and - why each one failed to load.
Activity
pavly-gerges commentedon Sep 18, 2026
There is an Exception class dedicated to this:
https://github.com/Electrostat-Lab/jSnapLoader/blob/master/snaploader%2Fsrc%2Fmain%2Fjava%2Felectrostatic4j%2Fsnaploader%2Fthrowable%2FUnSupportedSystemError.java
It might be the case that the caller function misbehaves.
stephengold commentedon Sep 22, 2026
Perhaps a concrete example will clarify the issue.
I modified TestBasicFeatures.java to report whether
loadLibrary()throws an exception:Then I replaced the
NativeDynamicLibraryfor my platform with an invalid entry:When I execute this modified
TestBasicFeatures, no exception is thrown.pavly-gerges commentedon Sep 23, 2026
During the initialization stage; this function should throw an
UnSupportedSystemErrorprior to calling the loading command.jSnapLoader/snaploader/src/main/java/electrostatic4j/snaploader/NativeBinaryLoader.java
Lines 126 to 159 in b19346f
Please verify whether the output log has an
UnSupportedSystemError.stephengold commentedon Sep 23, 2026
That error was not thrown because
isSystemFound[0]wastruein line 146.pavly-gerges commentedon Oct 4, 2026
The file locator system throws these, when a non-existent library is trying to be located:
Do you recognize these at your runtime logs?
However, if a broken file already exists; an
UnSatisfiedLinkErroris thrown because the file is too short (i.e., Corrupted file):stephengold commentedon Oct 4, 2026
Here's the complete output of "TestBasicFeatures.java" running on Linux with the changes described above:
How is the application supposed to detect that extraction has failed?
pavly-gerges commentedon Oct 4, 2026
I've just found the problem and its solution; the problem is that the Java Legacy
FileOutputStreamcreates anew Filewhen it's initialized regardless of whether a physical file pre-existed, which in our case leads to a creation of blank file that is too short or corrupt to be loadable by the dynamic loader.... The result cannot be avoided by jSnapLoader, so the solution is to delete that blank file when the library locator has failed...The
UnSatisfiedLinkErrorthrown in this case is not as result of trying to invoke a native function, but rather as a result of trying to load a bad file that is not a native binary.I will submit a PR and let's continue discussion there.