swiftlang/swift-java-jni-core

Swift Java Interoperability

Swift offers Java interoperability using the SwiftJava package, package plugins, and also the swift-java command line tool for source generation (similar to OpenJDK jextract, if you are familiar with that concept).

Most developers would benefit from using the SwiftJava package, as it features robust ways to make your interop code safe and performant, by using either source generation (swift-java) when calling Swift from Java, or Swift macros (@JavaMethod, ...) when calling Java from Swift. Multiple safeguards and optimizations are built into the SwiftJava library and we highly recommend using it instead of this low level "raw JNI" package.

Swift Java JNI Core Features

JavaValue

A JavaValue describes a type that can be bridged with Java. JavaValue is the base protocol for bridging between Swift types and their Java counterparts via the Java Native Interface (JNI). It is suitable for describing both value types (such as Int32 or Bool) and object types.

JavaVirtualMachine

The JavaVirtualMachine provides access to a Java Virtual Machine (JVM), which can either be loaded from within a Swift process (via JNI_CreateJavaVM), or accessed from a pre-existing in-process handle (JNI_GetCreatedJavaVMs). The JavaVirtualMachine is the entry point to interfacing with the JVM, and handles finding and loading classes, looking up and invoking methods, and handling details like locking, threads, and references.

CSwiftJavaJNI

This C module provides the standardized and implementation-agnostic headers for the Java Native Interface specification. The shape of these structures and symbols are guaranteed to be ABI stable between any compatible Java implementation.

Contributing

Contributions are more than welcome, and you can read more about the process in CONTRIBUTING.md.

Package Metadata

Repository: swiftlang/swift-java-jni-core

Default branch: main

README: README.md