How to load a JNI .dylib file with a dependency without getting an UnsatifiedLinkError?

Goal: Link Java to Swift

Problem: I get an UnsatisfiedLinkError when trying to load a JNI .dylib file that is linked with a Swift .dylib file when calling System#loadLibrary(String).

Expected Behavior: The dependency of the Java .dylib would be automatically loaded or the call to System.loadLibrary("SwiftCode") would load the dependency (the only solution I could come up with).

Note: I am combining this github tutorial and this Medium article to create my JNI .dylib file and this tutorial to create my Swift .dylib file.

Full stacktrace:

Exception in thread "main" java.lang.UnsatisfiedLinkError: /Users/hillmacbookpro/IdeaProjects/JavaToSwift/src/native/libSwiftHelloWorld.dylib: dlopen(/Users/hillmacbookpro/IdeaProjects/JavaToSwift/src/native/libSwiftHelloWorld.dylib, 1): Library not loaded: libSwiftCode.dylib
  Referenced from: /Users/hillmacbookpro/IdeaProjects/JavaToSwift/src/native/libSwiftHelloWorld.dylib
  Reason: image not found
    at java.base/java.lang.ClassLoader$NativeLibrary.load0(Native Method)
    at java.base/java.lang.ClassLoader$NativeLibrary.load(ClassLoader.java:2408)
    at java.base/java.lang.ClassLoader$NativeLibrary.loadLibrary(ClassLoader.java:2465)
    at java.base/java.lang.ClassLoader.loadLibrary0(ClassLoader.java:2662)
    at java.base/java.lang.ClassLoader.loadLibrary(ClassLoader.java:2627)
    at java.base/java.lang.Runtime.loadLibrary0(Runtime.java:829)
    at java.base/java.lang.System.loadLibrary(System.java:1833)
    at helloworld.SwiftHelloWorld.<clinit>(SwiftHelloWorld.java:7)

File Structure:

src
  - helloworld
      - SwiftHelloWorld.java
  - native
      - libSwiftHelloWorld.dylib
      - libSwiftCode.dylib

MCVE:

SwiftHelloWorld.java:

package helloworld;

public class SwiftHelloWorld {

    static {
        System.loadLibrary("SwiftCode"); // loading SwiftHelloWorld's dependency first
        System.loadLibrary("SwiftHelloWorld"); // exception thrown here, can't find dependency?
    }

    public static native void printHelloWorldImpl();

    public static void main(final String[] args) {
        printHelloWorldImpl();
    }

}

libSwiftHelloWorld.dylib: Created using these two terminal commands:

export JAVA_HOME="$(/usr/libexec/java_home -v 11)"; gcc -I"$JAVA_HOME/include" -I"$JAVA_HOME/include/darwin/" -o libSwiftHelloWorld.dylib -dynamiclib helloworld_SwiftHelloWorld.c libSwiftCode.dylib

and these files:

• helloworld_SwiftHelloWorld.c:

  #include <jni.h>
  #include <stdio.h>
  #include "helloworld_SwiftHelloWorld.h"
  #include "helloworld_SwiftHelloWorld_swift.h"
  
  JNIEXPORT void JNICALL Java_helloworld_SwiftHelloWorld_printHelloWorldImpl
    (JNIEnv *env, jclass clazz) {
  
      int result = swiftHelloWorld(42);
      printf("%s%i%s", "Hello World from JNI! ", result, "\n");
  
  }
  

• helloworld_SwiftHelloWorld.h: The auto-generated JNI header from javac -h native/ helloworld/SwiftHelloWorld.java

• helloworld_SwiftHelloWorld_swift.h:

  int swiftHelloWorld(int);
  

libSwiftCode.dylib: Created using swiftc SwiftCode.swift -emit-library -o libSwiftCode.dylib and the SwiftCode.swift file:

import Foundation

// force the function to have a name callable by the c code
@_silgen_name("swiftHelloWorld")
public func swiftHelloWorld(number: Int) -> Int {
    print("Hello world from Swift: \(number)")
    return 69
}

Related Questions:

• Java JNI linking multiple libraries, he/she gets an UnsatifiedLinkError but with the discription undefined symbol: ... (unanswered)

• Anything tagged with JNI and containing UnsatifiedLinkError

Other Notes: I am setting the Java virtual machine's options to -Djava.library.path=src/native, the parent directory of both of the .dylib files. I am using macOS.

Edit: I have tried preceding the command to compile SwiftCode.swift with xcrun as seen in this article (under "Compile Swift code") but I still get the same error.