Undefined symbol: _JNI_CreateJavaVM & _JNI_GetCreatedJavaVMs during building Xcode project

从报告中的 Package.swift linkerSettings 以及 SwiftJava 和 CSwiftJavaJNI products 开始，然后比较成功的 swift build 与在 arm64 上失败的 Xcode macOS build。使用提供的 Java 和 toolchain 详细信息重现未定义的 _JNI_CreateJavaVM 和 _JNI_GetCreatedJavaVMs 错误。当 Xcode project 能够链接 JNI symbols，同时保留生成的 Swift Java types 时，即表示完成。

Commit hash: d087f65caa3dfb1f0582568ce6e2ee0cf69ed717

Context:

I have built simple Swift package, that contains jar file and uses SwiftJava to get artifacts of Java types that were declared in that .jar file, to use them inside the library. I have provided swift-java.config file for desired types.

I used swift build command for the package. Which resulted in successful building and corresponding Swift's representation of Java types were generated in .build directory of my package. So, from my understanding I have set everything up correctly, otherwise those files wouldn't even be generated.

But, once I added this local package to Xcode macOS project I keep getting error from SwiftJava package, which prevents my project from building:

Undefined symbol: _JNI_CreateJavaVM
Undefined symbol: _JNI_GetCreatedJavaVMs

Undefined symbols for architecture arm64:
  "_JNI_CreateJavaVM", referenced from:
      SwiftJava.JavaVirtualMachine.(in _6C47C84FF2986D473D4896464216BF8F).init(classpath: [Swift.String], vmOptions: [Swift.String], ignoreUnrecognized: Swift.Bool) throws -> SwiftJava.JavaVirtualMachine in SwiftJava.o
  "_JNI_GetCreatedJavaVMs", referenced from:
      closure #2 @Sendable (inout SwiftJava.JavaVirtualMachine?) throws -> SwiftJava.JavaVirtualMachine in static SwiftJava.JavaVirtualMachine.shared(classpath: [Swift.String], vmOptions: [Swift.String], ignoreUnrecognized: Swift.Bool, replace: Swift.Bool) throws -> SwiftJava.JavaVirtualMachine in SwiftJava.o
ld: symbol(s) not found for architecture arm64

I have tried to specify path for linker in my Package.swift file, in order to find correct libjvm.dylib file, but that doesn't seem to be related to this, since SwiftJava is complaining.

Package.swift content of my package I'm adding to my project

// swift-tools-version: 6.2
// The swift-tools-version declares the minimum version of Swift required to build this package.
import CompilerPluginSupport
import PackageDescription
import class Foundation.FileManager
import class Foundation.ProcessInfo

func findJavaHome() -> String {
    if let home: String = ProcessInfo.processInfo.environment["JAVA_HOME"] {
        return home
    }
    
    let path = "\(FileManager.default.homeDirectoryForCurrentUser.path()).java_home"
    
    if let home: String = try? String(contentsOfFile: path, encoding: .utf8) {
        if let lastChar = home.last, lastChar.isNewline {
            return String(home.dropLast())
        }
        
        return home
    }
    
    fatalError("Please set the JAVA_HOME environment variable to point where Java is installed: \(path)")
}

let java_home = findJavaHome()

let javaIncludePath = "\(java_home)/include"
let javaPlatformIncludePath = "\(javaIncludePath)/darwin"

let homebrewJavaPath = "/opt/homebrew/opt/openjdk/libexec/openjdk.jdk/Contents/Home"

let package = Package(
    name: "MyPackage",
    platforms: [.macOS(.v15)],
    products: [.library(name: "MyPackage", type: .dynamic, targets: ["MyPackage"])],
    dependencies: [
        .package(url: "https://github.com/swiftlang/swift-java", branch: "main")
    ],
    targets: [
        // Targets are the basic building blocks of a package, defining a module or a test suite.
        // Targets can depend on other targets in this package and products from dependencies.
        .target(
            name: "MyPackage",
            dependencies: [
                .product(name: "SwiftJava", package: "swift-java"),
                .product(name: "CSwiftJavaJNI", package: "swift-java"),
                .product(name: "SwiftJavaConfigurationShared", package: "swift-java"),
                .product(name: "SwiftRuntimeFunctions", package: "swift-java")
            ],
            exclude: ["swift-java.config"],
            swiftSettings: [
                .unsafeFlags(["-I\(javaIncludePath)", "-I\(javaPlatformIncludePath)"]),
                .swiftLanguageMode(.v5)
            ],
            linkerSettings: [
                    .unsafeFlags([
                        "-L\(homebrewJavaPath)/lib/server",
                        "-ljvm"
                    ])
                ],
            plugins: [
                .plugin(name: "JExtractSwiftPlugin", package: "swift-java"),
                .plugin(name: "SwiftJavaPlugin", package: "swift-java")
            ]
        ),
    ]
)

Probably some relevant info about system:

MacBook Air M1
Operating system: MacOS 26.2
swift-driver version: 1.127.14.1 Apple Swift version 6.2.1 (swiftlang-6.2.1.4.8 clang-1700.4.4.1)
Target: arm64-apple-macosx26.0

/usr/libexec/java_home -V:
Matching Java Virtual Machines (1):
25.0.2 (arm64) "Homebrew" - "OpenJDK 25.0.2" /opt/homebrew/Cellar/openjdk/25.0.2/libexec/openjdk.jdk/Contents/Home

java -version:
openjdk version "25.0.2" 2026-01-20
OpenJDK Runtime Environment Homebrew (build 25.0.2)
OpenJDK 64-Bit Server VM Homebrew (build 25.0.2, mixed mode, sharing)