Endive 1.0: WebAssembly on the JVM, Now a Bytecode Alliance Project

We're excited to announce Endive 1.0, the first release of the project under the Bytecode Alliance. Endive is a pure-Java WebAssembly runtime with zero native dependencies, continuing the work started as Chicory. For background on the move, see the announcement article. If you're migrating from Chicory, the migration guide has you covered.

WasmGC Host Integration

The Java garbage collector now manages WasmGC objects. Structs, arrays, and externref values that cross the Wasm/Java boundary are standard Java Objects on the JVM heap. No separate GC store, no manual reference tracking. They get collected when unreachable, just like any other object in your application.

The annotation processor supports externref as plain Object, so host functions work naturally with GC types.

If you use WasmGC types at the host boundary, your code will need a small update. Here's what changed.

Calling exports that use GC types

Use applyWithRefs instead of apply. It returns a CallResult with separate accessors for numeric and reference results:

// Before: not possible, GC refs were opaque ints
long[] result = export.apply(args);

// After: GC refs flow as Java Objects
CallResult result = export.applyWithRefs(new long[]{42, 10}, null);
WasmStruct point = (WasmStruct) result.refResult(0);
int x = (int) point.field(0);

Calling apply() on a function that involves GC types will throw.

Building structs and arrays

Old constructors are deprecated. Use the builder:

// Before
var struct = new WasmStruct(typeIdx, new long[]{1, 2});

// After: add fields in declaration order
var struct = WasmStruct.builder()
    .typeIdx(typeIdx)
    .addField(42)        // field 0: numeric
    .addFieldRef(someRef) // field 1: reference
    .build();

int x = (int) struct.field(0);      // read numeric field
Object r = struct.fieldRef(1);      // read ref field

WasmArray follows the same pattern with addElement() / addElementRef().

Host functions receiving GC types

Override applyWithRefs on WasmFunctionHandle:

WasmFunctionHandle myFunc = new WasmFunctionHandle() {
    @Override
    public CallResult applyWithRefs(Instance instance, long[] args, Object[] refArgs) {
        WasmStruct input = (WasmStruct) refArgs[0];
        // ... process the struct
        return CallResult.of(new long[]{result}, null);
    }
};

See #55 for the full set of changes.

Tail Call Optimizations

Community-contributed fixes have improved tail call correctness, and the compiler now optimizes tail-call dispatch by eliminating unnecessary stack frame allocation. CPython 3.14, which adopted tail calls in its interpreter loop, is the main beneficiary.

Migrating from Chicory

For most users, migrating is a find-and-replace. Maven coordinates move from com.dylibso.chicory to run.endive, Java packages move from com.dylibso.chicory.* to run.endive.*, and two exception classes have been renamed (ChicoryException to WasmEngineException, ChicoryInterruptedException to WasmInterruptedException). The migration guide covers the full list, including Maven plugin goals, system properties, and CLI binary names.

If you use WasmGC types at the host boundary, see the section above.

What's Ahead

Community members have already started prototyping Component Model support at endive-cm. Anyone interested is welcome to contribute. Follow #52 for updates. Cranelift-based native compilation is also in the works, bringing near-native execution speed while preserving the pure-Java packaging experience.

Acknowledgements

Thank you to every contributor who has shipped code, reported bugs, tested pre-releases, and pushed WebAssembly forward on the JVM. The adopters list, from JRuby to Trino, from Bazel to Apache Camel, is the best evidence that this runtime is solving real problems.

Getting Started

<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>run.endive</groupId>
            <artifactId>bom</artifactId>
            <version>1.0</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
    </dependencies>
</dependencyManagement>

<dependency>
    <groupId>run.endive</groupId>
    <artifactId>runtime</artifactId>
</dependency>

Documentation | GitHub

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