Objective-C Errors when building

[pnewell]

I am getting a bunch of objective-c errors when trying to run make javakit-run (see below)

I am one an M3 MacBook Air.

This is java --version:

openjdk 23.0.1 2024-10-15
OpenJDK Runtime Environment (build 23.0.1+11-39)
OpenJDK 64-Bit Server VM (build 23.0.1+11-39, mixed mode, sharing)

Java was installed with brew (openjdk) and JAVA_HOME is pointed at /Users/REDACTED/Library/Java/JavaVirtualMachines/openjdk-23.0.1/Contents/Home

This is swift --version:

Apple Swift version 6.1-dev (LLVM c7635515f932833, Swift dbf388c0a58df0e)
Target: arm64-apple-macosx15.0

Here are the errors:

Writing Java class 'com.example.swift.HelloSubclass' translation to '/Users/REDACTED/Downloads/swift-java-main/Samples/JavaKitSampleApp/.build/plugins/outputs/javakitsampleapp/JavaKitExample/destination/Java2SwiftPlugin/generated/HelloSubclass.swift'... done.
Writing Java class 'com.example.swift.JavaKitSampleMain' translation to '/Users/REDACTED/Downloads/swift-java-main/Samples/JavaKitSampleApp/.build/plugins/outputs/javakitsampleapp/JavaKitExample/destination/Java2SwiftPlugin/generated/JavaKitSampleMain.swift'... done.
Writing Java class 'com.example.swift.HelloSwift' translation to '/Users/REDACTED/Downloads/swift-java-main/Samples/JavaKitSampleApp/.build/plugins/outputs/javakitsampleapp/JavaKitExample/destination/Java2SwiftPlugin/generated/HelloSwift.swift'... done.
/Users/REDACTED/Downloads/swift-java-main/Samples/JavaKitSampleApp/.build/arm64-apple-macosx/debug/JavaRuntime-tool.build/module.modulemap:1:8: error: redefinition of module 'JavaRuntime'
1 | module JavaRuntime {
  |        `- error: redefinition of module 'JavaRuntime'
2 |     umbrella header "/Users/REDACTED/Downloads/swift-java-main/Sources/JavaRuntime/include/JavaRuntime.h"
3 |     export *

/Users/REDACTED/Downloads/swift-java-main/Samples/JavaKitSampleApp/.build/arm64-apple-macosx/debug/JavaRuntime.build/module.modulemap:1:8: note: previously defined here
1 | module JavaRuntime {
  |        `- note: previously defined here
2 |     umbrella header "/Users/REDACTED/Downloads/swift-java-main/Sources/JavaRuntime/include/JavaRuntime.h"
3 |     export *

<unknown>:0: error: could not build Objective-C module 'SwiftShims'
/Users/REDACTED/Downloads/swift-java-main/Samples/JavaKitSampleApp/.build/arm64-apple-macosx/debug/JavaRuntime-tool.build/module.modulemap:1:8: error: redefinition of module 'JavaRuntime'
1 | module JavaRuntime {
  |        `- error: redefinition of module 'JavaRuntime'
2 |     umbrella header "/Users/REDACTED/Downloads/swift-java-main/Sources/JavaRuntime/include/JavaRuntime.h"
3 |     export *

/Users/REDACTED/Downloads/swift-java-main/Samples/JavaKitSampleApp/.build/arm64-apple-macosx/debug/JavaRuntime.build/module.modulemap:1:8: note: previously defined here
1 | module JavaRuntime {
  |        `- note: previously defined here
2 |     umbrella header "/Users/REDACTED/Downloads/swift-java-main/Sources/JavaRuntime/include/JavaRuntime.h"
3 |     export *
/Users/REDACTED/Downloads/swift-java-main/Samples/JavaKitSampleApp/.build/arm64-apple-macosx/debug/JavaRuntime-tool.build/module.modulemap:1:8: error: redefinition of module 'JavaRuntime'
1 | module JavaRuntime {
  |        `- error: redefinition of module 'JavaRuntime'
2 |     umbrella header "/Users/REDACTED/Downloads/swift-java-main/Sources/JavaRuntime/include/JavaRuntime.h"
3 |     export *

/Users/REDACTED/Downloads/swift-java-main/Samples/JavaKitSampleApp/.build/arm64-apple-macosx/debug/JavaRuntime.build/module.modulemap:1:8: note: previously defined here
1 | module JavaRuntime {
  |        `- note: previously defined here
2 |     umbrella header "/Users/REDACTED/Downloads/swift-java-main/Sources/JavaRuntime/include/JavaRuntime.h"
3 |     export *

<unknown>:0: error: could not build Objective-C module 'SwiftShims'
/Users/REDACTED/Downloads/swift-java-main/Samples/JavaKitSampleApp/.build/arm64-apple-macosx/debug/JavaRuntime-tool.build/module.modulemap:1:8: error: redefinition of module 'JavaRuntime'
1 | module JavaRuntime {
  |        `- error: redefinition of module 'JavaRuntime'
2 |     umbrella header "/Users/REDACTED/Downloads/swift-java-main/Sources/JavaRuntime/include/JavaRuntime.h"
3 |     export *

/Users/REDACTED/Downloads/swift-java-main/Samples/JavaKitSampleApp/.build/arm64-apple-macosx/debug/JavaRuntime.build/module.modulemap:1:8: note: previously defined here
1 | module JavaRuntime {
  |        `- note: previously defined here
2 |     umbrella header "/Users/REDACTED/Downloads/swift-java-main/Sources/JavaRuntime/include/JavaRuntime.h"
3 |     export *
/Users/REDACTED/Downloads/swift-java-main/Samples/JavaKitSampleApp/.build/arm64-apple-macosx/debug/JavaRuntime-tool.build/module.modulemap:1:8: error: redefinition of module 'JavaRuntime'
1 | module JavaRuntime {
  |        `- error: redefinition of module 'JavaRuntime'
2 |     umbrella header "/Users/REDACTED/Downloads/swift-java-main/Sources/JavaRuntime/include/JavaRuntime.h"
3 |     export *

/Users/REDACTED/Downloads/swift-java-main/Samples/JavaKitSampleApp/.build/arm64-apple-macosx/debug/JavaRuntime.build/module.modulemap:1:8: note: previously defined here
1 | module JavaRuntime {
  |        `- note: previously defined here
2 |     umbrella header "/Users/REDACTED/Downloads/swift-java-main/Sources/JavaRuntime/include/JavaRuntime.h"
3 |     export *

<unknown>:0: error: could not build Objective-C module 'SwiftShims'
/Users/REDACTED/Downloads/swift-java-main/Samples/JavaKitSampleApp/.build/arm64-apple-macosx/debug/JavaRuntime-tool.build/module.modulemap:1:8: error: redefinition of module 'JavaRuntime'
1 | module JavaRuntime {
  |        `- error: redefinition of module 'JavaRuntime'
2 |     umbrella header "/Users/REDACTED/Downloads/swift-java-main/Sources/JavaRuntime/include/JavaRuntime.h"
3 |     export *

/Users/REDACTED/Downloads/swift-java-main/Samples/JavaKitSampleApp/.build/arm64-apple-macosx/debug/JavaRuntime.build/module.modulemap:1:8: note: previously defined here
1 | module JavaRuntime {
  |        `- note: previously defined here
2 |     umbrella header "/Users/REDACTED/Downloads/swift-java-main/Sources/JavaRuntime/include/JavaRuntime.h"
3 |     export *
error: emit-module command failed with exit code 1 (use -v to see invocation)
/Users/REDACTED/Downloads/swift-java-main/Samples/JavaKitSampleApp/.build/arm64-apple-macosx/debug/JavaRuntime-tool.build/module.modulemap:1:8: error: redefinition of module 'JavaRuntime'
1 | module JavaRuntime {
  |        `- error: redefinition of module 'JavaRuntime'
2 |     umbrella header "/Users/REDACTED/Downloads/swift-java-main/Sources/JavaRuntime/include/JavaRuntime.h"
3 |     export *

/Users/REDACTED/Downloads/swift-java-main/Samples/JavaKitSampleApp/.build/arm64-apple-macosx/debug/JavaRuntime.build/module.modulemap:1:8: note: previously defined here
1 | module JavaRuntime {
  |        `- note: previously defined here
2 |     umbrella header "/Users/REDACTED/Downloads/swift-java-main/Sources/JavaRuntime/include/JavaRuntime.h"
3 |     export *

<unknown>:0: error: could not build Objective-C module 'SwiftShims'
/Users/REDACTED/Downloads/swift-java-main/Samples/JavaKitSampleApp/.build/arm64-apple-macosx/debug/JavaRuntime-tool.build/module.modulemap:1:8: error: redefinition of module 'JavaRuntime'
1 | module JavaRuntime {
  |        `- error: redefinition of module 'JavaRuntime'
2 |     umbrella header "/Users/REDACTED/Downloads/swift-java-main/Sources/JavaRuntime/include/JavaRuntime.h"
3 |     export *

/Users/REDACTED/Downloads/swift-java-main/Samples/JavaKitSampleApp/.build/arm64-apple-macosx/debug/JavaRuntime.build/module.modulemap:1:8: note: previously defined here
1 | module JavaRuntime {
  |        `- note: previously defined here
2 |     umbrella header "/Users/REDACTED/Downloads/swift-java-main/Sources/JavaRuntime/include/JavaRuntime.h"
3 |     export *
/Users/REDACTED/Downloads/swift-java-main/Samples/JavaKitSampleApp/.build/arm64-apple-macosx/debug/JavaRuntime-tool.build/module.modulemap:1:8: error: redefinition of module 'JavaRuntime'
1 | module JavaRuntime {
  |        `- error: redefinition of module 'JavaRuntime'
2 |     umbrella header "/Users/REDACTED/Downloads/swift-java-main/Sources/JavaRuntime/include/JavaRuntime.h"
3 |     export *

/Users/REDACTED/Downloads/swift-java-main/Samples/JavaKitSampleApp/.build/arm64-apple-macosx/debug/JavaRuntime.build/module.modulemap:1:8: note: previously defined here
1 | module JavaRuntime {
  |        `- note: previously defined here
2 |     umbrella header "/Users/REDACTED/Downloads/swift-java-main/Sources/JavaRuntime/include/JavaRuntime.h"
3 |     export *

<unknown>:0: error: could not build Objective-C module 'SwiftShims'
/Users/REDACTED/Downloads/swift-java-main/Samples/JavaKitSampleApp/.build/arm64-apple-macosx/debug/JavaRuntime-tool.build/module.modulemap:1:8: error: redefinition of module 'JavaRuntime'
1 | module JavaRuntime {
  |        `- error: redefinition of module 'JavaRuntime'
2 |     umbrella header "/Users/REDACTED/Downloads/swift-java-main/Sources/JavaRuntime/include/JavaRuntime.h"
3 |     export *

/Users/REDACTED/Downloads/swift-java-main/Samples/JavaKitSampleApp/.build/arm64-apple-macosx/debug/JavaRuntime.build/module.modulemap:1:8: note: previously defined here
1 | module JavaRuntime {
  |        `- note: previously defined here
2 |     umbrella header "/Users/REDACTED/Downloads/swift-java-main/Sources/JavaRuntime/include/JavaRuntime.h"
3 |     export *
/Users/REDACTED/Downloads/swift-java-main/Samples/JavaKitSampleApp/.build/arm64-apple-macosx/debug/JavaRuntime-tool.build/module.modulemap:1:8: error: redefinition of module 'JavaRuntime'
1 | module JavaRuntime {
  |        `- error: redefinition of module 'JavaRuntime'
2 |     umbrella header "/Users/REDACTED/Downloads/swift-java-main/Sources/JavaRuntime/include/JavaRuntime.h"
3 |     export *

/Users/REDACTED/Downloads/swift-java-main/Samples/JavaKitSampleApp/.build/arm64-apple-macosx/debug/JavaRuntime.build/module.modulemap:1:8: note: previously defined here
1 | module JavaRuntime {
  |        `- note: previously defined here
2 |     umbrella header "/Users/REDACTED/Downloads/swift-java-main/Sources/JavaRuntime/include/JavaRuntime.h"
3 |     export *

<unknown>:0: error: could not build Objective-C module 'SwiftShims'
/Users/REDACTED/Downloads/swift-java-main/Samples/JavaKitSampleApp/.build/arm64-apple-macosx/debug/JavaRuntime-tool.build/module.modulemap:1:8: error: redefinition of module 'JavaRuntime'
1 | module JavaRuntime {
  |        `- error: redefinition of module 'JavaRuntime'
2 |     umbrella header "/Users/REDACTED/Downloads/swift-java-main/Sources/JavaRuntime/include/JavaRuntime.h"
3 |     export *

/Users/REDACTED/Downloads/swift-java-main/Samples/JavaKitSampleApp/.build/arm64-apple-macosx/debug/JavaRuntime.build/module.modulemap:1:8: note: previously defined here
1 | module JavaRuntime {
  |        `- note: previously defined here
2 |     umbrella header "/Users/REDACTED/Downloads/swift-java-main/Sources/JavaRuntime/include/JavaRuntime.h"
3 |     export *

make: *** [javakit-run] Error 1

[ktoso]

Hi there, thanks for trying out the project and sorry about the current state of the build, we're ironing out things and trying to get away make driving things.

Specifically for this sample, please follow the readme: https://github.com/swiftlang/swift-java?tab=readme-ov-file#javakit-swift---java

JavaKit (Swift -> Java)

To run a simple app showcasing a Swift process calling into a Java library you can run:

cd Samples/JavaKitSampleApp
swift build
java -cp .build/plugins/outputs/javakitsampleapp/JavaKitExample/destination/JavaCompilerPlugin/Java -Djava.library.path=.build/debug com.example.swift.JavaKitSampleMain

rather than rely on the make task; I'll remove the make task so it's not confusing folks anymore

[dschaefer2]

This appears to be a bug in SwiftPM. We have a similar report swiftlang/swift-package-manager#8436.

[ykws]

@dschaefer2 Thanks for the pointer to the SwiftPM issue. I’ve just confirmed that PR swiftlang/swift-package-manager#8472 was merged into the release/6.2 branch. Does that mean the JavaRuntime redefinition error should be fixed in the Swift 6.2 (May 7, 2025) toolchain? In other words, if I download and install the release/6.2 .pkg from swift.org, I’ll be getting a toolchain that includes this fix—does that sound right?

% xcrun --toolchain swift swift --version
Apple Swift version 6.2-dev (LLVM 815013bbc318474, Swift 1459ecafa998782)
Target: arm64-apple-macosx15.0
Build config: +assertions

[rintaro]

#285