hello-swift-java: JAVA_HOME in Android Studio builds

[carson-katri]

I tried to build the basic hello-swift-java-hashing-app example through Android Studio. However, it fails to build with a missing JAVA_HOME path.

error: 'hashing-lib': Invalid manifest (compiled with: ["~/Library/Developer/Toolchains/swift-DEVELOPMENT-SNAPSHOT-2025-10-16-a.xctoolchain/usr/bin/swiftc", "-vfsoverlay", "/var/folders/47/kzjdq9x56dj77sc4xng5nc180000gp/T/TemporaryDirectory.Va6pCT/vfs.yaml", "-L", "~/Library/Developer/Toolchains/swift-DEVELOPMENT-SNAPSHOT-2025-10-16-a.xctoolchain/usr/lib/swift/pm/ManifestAPI", "-lPackageDescription", "-Xlinker", "-rpath", "-Xlinker", "~/Library/Developer/Toolchains/swift-DEVELOPMENT-SNAPSHOT-2025-10-16-a.xctoolchain/usr/lib/swift/pm/ManifestAPI", "-target", "arm64-apple-macosx14.0", "-I", "~/Library/Developer/Toolchains/swift-DEVELOPMENT-SNAPSHOT-2025-10-16-a.xctoolchain/usr/lib/swift/macosx/testing", "-L", "~/Library/Developer/Toolchains/swift-DEVELOPMENT-SNAPSHOT-2025-10-16-a.xctoolchain/usr/lib/swift/macosx/testing", "-plugin-path", "~/Library/Developer/Toolchains/swift-DEVELOPMENT-SNAPSHOT-2025-10-16-a.xctoolchain/usr/lib/swift/host/plugins/testing", "-sdk", "/Applications/Xcode-26.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX26.0.sdk", "-F", "/Applications/Xcode-26.app/Contents/Developer/Platforms/MacOSX.platform/Developer/Library/Frameworks", "-F", "/Applications/Xcode-26.app/Contents/Developer/Platforms/MacOSX.platform/Developer/Library/PrivateFrameworks", "-I", "/Applications/Xcode-26.app/Contents/Developer/Platforms/MacOSX.platform/Developer/usr/lib", "-L", "/Applications/Xcode-26.app/Contents/Developer/Platforms/MacOSX.platform/Developer/usr/lib", "-swift-version", "6", "-I", "~/Library/Developer/Toolchains/swift-DEVELOPMENT-SNAPSHOT-2025-10-16-a.xctoolchain/usr/lib/swift/pm/ManifestAPI", "-sdk", "/Applications/Xcode-26.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX26.0.sdk", "-package-description-version", "6.2.0", "~/Downloads/swift-android-examples/hello-swift-java/hashing-lib/Package.swift", "-o", "/var/folders/47/kzjdq9x56dj77sc4xng5nc180000gp/T/TemporaryDirectory.9yfWJ3/hashing-lib-manifest"])
main/Package.swift:29: Fatal error: Please set the JAVA_HOME environment variable to point to where Java is installed.

I have a couple of questions about the setup:

• Should the build.gradle set the JAVA_HOME, or should this be set globally for my system?
• Should it be the JAVA_HOME from Android Studio, or the one from sdkman used to build the local packages?

Sorry if I'm missing something obvious, I'm not very familiar with Android development.

When building the .aar from the command line with ./gradlew :hello-swift-java-hashing-lib:assembleRelease, it successfully builds with JAVA_HOME set to the sdkman path.

[finagolfin]

@madsodgaard, know what's going on here?