[jni] Migrates java source build of jni from using maven to gradle

[jwill]

• Uses Gradle to build the java sources for jni
• Removes requirement for Maven to be installed to run jni
  Supercedes jni portions of [jnigen] standardize on using gradle to build all artifacts versus a mix of Maven and Gradle #1948

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[github-actions]

Package publishing

Package	Version	Status	Publish tag (post-merge)
package:ffi	2.1.4	ready to publish	ffi-v2.1.4
package:ffigen	17.0.0-wip	WIP (no publish necessary)
package:jni	0.14.1-wip	WIP (no publish necessary)
package:jnigen	0.14.1-wip	WIP (no publish necessary)
package:objective_c	6.0.0-wip	WIP (no publish necessary)
package:swift2objc	0.0.1-wip	WIP (no publish necessary)
package:swiftgen	0.0.1-wip	WIP (no publish necessary)

Documentation at https://github.com/dart-lang/ecosystem/wiki/Publishing-automation.

[github-actions]

PR Health

Breaking changes ✔️

Package	Change	Current Version	New Version	Needed Version	Looking good?
jni	None	0.14.0	0.14.1-wip	0.14.0	✔️

Changelog Entry ✔️

Package	Changed Files

Changes to files need to be accounted for in their respective changelogs.

API leaks ⚠️

The following packages contain symbols visible in the public API, but not exported by the library. Export these symbols or remove them from your publicly visible API.

Package	Leaked API symbols
jni	_opaque_pthread_mutex_t _opaque_pthread_cond_t _Dart_FinalizableHandle _ReferenceType

This check can be disabled by tagging the PR with skip-leaking-check.

License Headers ✔️

// Copyright (c) 2025, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

Files
no missing headers

All source files should start with a license header.

Unrelated files missing license headers

Files
pkgs/jni/lib/src/third_party/generated_bindings.dart
pkgs/objective_c/lib/src/ns_input_stream.dart

[github-actions]

PR Health

Breaking changes ✔️

Package	Change	Current Version	New Version	Needed Version	Looking good?
jni	None	0.14.0	0.14.0	0.14.0	✔️

Changelog Entry ❗

Package	Changed Files
package:jni	pkgs/jni/bin/setup.dart

Changes to files need to be accounted for in their respective changelogs.

This check can be disabled by tagging the PR with skip-changelog-check.

API leaks ⚠️

The following packages contain symbols visible in the public API, but not exported by the library. Export these symbols or remove them from your publicly visible API.

Package	Leaked API symbols
jni	_opaque_pthread_mutex_t _opaque_pthread_cond_t _Dart_FinalizableHandle _ReferenceType

This check can be disabled by tagging the PR with skip-leaking-check.

License Headers ✔️

// Copyright (c) 2025, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

Files
no missing headers

All source files should start with a license header.

Unrelated files missing license headers

Files
pkgs/jni/lib/src/third_party/generated_bindings.dart
pkgs/objective_c/lib/src/ns_input_stream.dart

[coveralls]

coverage: 86.952% (-2.9%) from 89.811%
when pulling 87ce790 on jni-gradle
into 23a387d on main.

[HosseinYousefi]

LGTM! Thanks @jwill 🚀