Support pure JVM JAR compilation and packaging for desktop JVM

extension/android/CMakeLists.txt

@@ -1,3 +1,3 @@
 # Copyright (c) Meta Platforms, Inc. and affiliates.
 # All rights reserved.
 #
@@ -12,65 +12,84 @@
   set(CMAKE_CXX_STANDARD 17)
 endif()
 
-if(NOT ANDROID)
-  message(FATAL_ERROR "This directory is for Android build only")
-endif()
-
 set(EXECUTORCH_ROOT "${CMAKE_CURRENT_SOURCE_DIR}/../..")
 include(${EXECUTORCH_ROOT}/tools/cmake/Utils.cmake)
-set(_common_compile_options
-    $<$<CXX_COMPILER_ID:MSVC>:/wd4996>
-    $<$<NOT:$<CXX_COMPILER_ID:MSVC>>:-Wno-deprecated-declarations -fPIC>
-)
-if(NOT ANDROID_PLATFORM)
-  set(ANDROID_PLATFORM android-30)
-endif()
 
-# We need to download fbjni library from maven, and use its "prefab" library and
-# headers, and link executorch library against that fbjni library. We don't know
-# which NDK is used to compile fbjni, and we need to link our executorch library
-# to the version which Android APK links against for runtime to ensure the
-# libc++ dependencies are consistent. WARNING # Users need to use the SAME fbjni
-# version here and in app gradle dependency for runtime compatibility!
-if(NOT FBJNI_VERSION)
-  set(FBJNI_VERSION 0.7.0)
-endif()
+if(NOT ANDROID)
+  find_package(JNI REQUIRED)
+  if(NOT FBJNI_HEADERS_DIR OR NOT FBJNI_LIBRARY)
+    message(
+      FATAL_ERROR
+        "For non-Android platforms, please specify -DFBJNI_HEADERS_DIR=/path/to/fbjni/include and -DFBJNI_LIBRARY=/path/to/libfbjni.so"
+    )
+  endif()
 
-set(FBJNI_AAR_URL
-    https://repo1.maven.org/maven2/com/facebook/fbjni/fbjni/${FBJNI_VERSION}/fbjni-${FBJNI_VERSION}.aar
-)
-set(FBJNI_DOWNLOAD_PATH ${CMAKE_CURRENT_BINARY_DIR}/third-party/fbjni/fbjni.aar)
+  add_library(fbjni SHARED IMPORTED)
+  set_target_properties(fbjni PROPERTIES IMPORTED_LOCATION "${FBJNI_LIBRARY}")
+  set(_common_compile_options
+      $<$<CXX_COMPILER_ID:MSVC>:/wd4996>
+      $<$<NOT:$<CXX_COMPILER_ID:MSVC>>:-Wno-deprecated-declarations -fPIC>
+  )
+else()
+  set(_common_compile_options
+      $<$<CXX_COMPILER_ID:MSVC>:/wd4996>
+      $<$<NOT:$<CXX_COMPILER_ID:MSVC>>:-Wno-deprecated-declarations -fPIC>
+  )
+  if(NOT ANDROID_PLATFORM)
+    set(ANDROID_PLATFORM android-30)
+  endif()
 
-if(NOT EXISTS "${FBJNI_DOWNLOAD_PATH}")
-  file(DOWNLOAD "${FBJNI_AAR_URL}" "${FBJNI_DOWNLOAD_PATH}")
-endif()
+  # We need to download fbjni library from maven, and use its "prefab" library
+  # and headers, and link executorch library against that fbjni library. We
+  # don't know which NDK is used to compile fbjni, and we need to link our
+  # executorch library to the version which Android APK links against for
+  # runtime to ensure the libc++ dependencies are consistent. WARNING # Users
+  # need to use the SAME fbjni version here and in app gradle dependency for
+  # runtime compatibility!
+  if(NOT FBJNI_VERSION)
+    set(FBJNI_VERSION 0.7.0)
+  endif()
 
-add_custom_command(
-  OUTPUT
-    "${CMAKE_CURRENT_BINARY_DIR}/third-party/fbjni/prefab/modules/fbjni/include/"
-    "${CMAKE_CURRENT_BINARY_DIR}/third-party/fbjni/prefab/modules/fbjni/libs/android.${ANDROID_ABI}/libfbjni.so"
-  COMMAND unzip -o ${FBJNI_DOWNLOAD_PATH} -d
-          ${CMAKE_CURRENT_BINARY_DIR}/third-party/fbjni
-  DEPENDS "${FBJNI_DOWNLOAD_PATH}"
-)
+  set(FBJNI_AAR_URL
+      https://repo1.maven.org/maven2/com/facebook/fbjni/fbjni/${FBJNI_VERSION}/fbjni-${FBJNI_VERSION}.aar
+  )
+  set(FBJNI_DOWNLOAD_PATH
+      ${CMAKE_CURRENT_BINARY_DIR}/third-party/fbjni/fbjni.aar
+  )
 
-add_custom_target(
-  fbjni_prefab
-  DEPENDS
-    "${CMAKE_CURRENT_BINARY_DIR}/third-party/fbjni/prefab/modules/fbjni/include/"
-    "${CMAKE_CURRENT_BINARY_DIR}/third-party/fbjni/prefab/modules/fbjni/libs/android.${ANDROID_ABI}/libfbjni.so"
-)
+  if(NOT EXISTS "${FBJNI_DOWNLOAD_PATH}")
+    file(DOWNLOAD "${FBJNI_AAR_URL}" "${FBJNI_DOWNLOAD_PATH}")
+  endif()
 
-add_library(fbjni SHARED IMPORTED)
-add_dependencies(fbjni fbjni_prefab)
-set_target_properties(
-  fbjni
-  PROPERTIES
-    IMPORTED_LOCATION
-    "${CMAKE_CURRENT_BINARY_DIR}/third-party/fbjni/prefab/modules/fbjni/libs/android.${ANDROID_ABI}/libfbjni.so"
-)
+  add_custom_command(
+    OUTPUT
+      "${CMAKE_CURRENT_BINARY_DIR}/third-party/fbjni/prefab/modules/fbjni/include/"
+      "${CMAKE_CURRENT_BINARY_DIR}/third-party/fbjni/prefab/modules/fbjni/libs/android.${ANDROID_ABI}/libfbjni.so"
+    COMMAND unzip -o ${FBJNI_DOWNLOAD_PATH} -d
+            ${CMAKE_CURRENT_BINARY_DIR}/third-party/fbjni
+    DEPENDS "${FBJNI_DOWNLOAD_PATH}"
+  )
+
+  add_custom_target(
+    fbjni_prefab
+    DEPENDS
+      "${CMAKE_CURRENT_BINARY_DIR}/third-party/fbjni/prefab/modules/fbjni/include/"
+      "${CMAKE_CURRENT_BINARY_DIR}/third-party/fbjni/prefab/modules/fbjni/libs/android.${ANDROID_ABI}/libfbjni.so"
+  )
 
-executorch_target_link_options_shared_lib(executorch)
+  add_library(fbjni SHARED IMPORTED)
+  add_dependencies(fbjni fbjni_prefab)
+  set_target_properties(
+    fbjni
+    PROPERTIES
+      IMPORTED_LOCATION
+      "${CMAKE_CURRENT_BINARY_DIR}/third-party/fbjni/prefab/modules/fbjni/libs/android.${ANDROID_ABI}/libfbjni.so"
+  )
+endif()
+
+if(ANDROID)
+  executorch_target_link_options_shared_lib(executorch)
+endif()
 
 add_library(
   executorch_jni SHARED jni/jni_layer.cpp jni/log.cpp jni/jni_layer_runtime.cpp
@@ -233,19 +252,35 @@
   include("${CMAKE_CURRENT_SOURCE_DIR}/fb/extended_targets/CMakeLists.txt")
 endif()
 
-target_include_directories(
-  executorch_jni
-  PRIVATE
-    ${_common_include_directories}
-    "${CMAKE_CURRENT_BINARY_DIR}/third-party/fbjni/prefab/modules/fbjni/include/"
-)
+if(ANDROID)
+  target_include_directories(
+    executorch_jni
+    PRIVATE
+      ${_common_include_directories}
+      "${CMAKE_CURRENT_BINARY_DIR}/third-party/fbjni/prefab/modules/fbjni/include/"
+  )
+else()
+  target_include_directories(
+    executorch_jni
+    PRIVATE
+      ${_common_include_directories}
+      ${FBJNI_HEADERS_DIR}
+      ${JNI_INCLUDE_DIRS}
+  )
+endif()
 
 target_compile_options(executorch_jni PUBLIC ${_common_compile_options})
 
-target_link_options(
-  executorch_jni PRIVATE
-  "LINKER:--version-script,${CMAKE_CURRENT_SOURCE_DIR}/jni/version_script.txt"
-)
+if(NOT WIN32)
+  target_link_options(
+    executorch_jni PRIVATE
+    "LINKER:--version-script,${CMAKE_CURRENT_SOURCE_DIR}/jni/version_script.txt"
+  )
+endif()
 target_link_options_gc_sections(executorch_jni)
 
-target_link_libraries(executorch_jni ${link_libraries} log)
+if(ANDROID)
+  target_link_libraries(executorch_jni ${link_libraries} log)
+else()
+  target_link_libraries(executorch_jni ${link_libraries} ${JNI_LIBRARIES})
+endif()

extension/android/build.gradle

@@ -12,9 +12,15 @@ allprojects {
 
         dependencies {
             classpath 'com.android.tools.build:gradle:8.9.0'
-            classpath 'com.vanniktech:gradle-maven-publish-plugin:0.34.0'
+            classpath 'com.vanniktech:gradle-maven-publish-plugin:0.31.0'
+            classpath 'com.diffplug.spotless:spotless-plugin-gradle:8.0.0'
+            classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:1.9.23"
         }
+    }
 
+    ext {
+        fbjniJavaOnlyVersion = "0.7.0"
+        soLoaderNativeLoaderVersion = "0.10.5"
     }
 
     repositories {

extension/android/executorch_android/build.gradle

@@ -7,12 +7,10 @@
  */
 
 
-plugins {
-    id "com.android.library" version "8.9.0"
-    id "com.vanniktech.maven.publish" version "0.31.0"
-    id 'com.diffplug.spotless' version '8.0.0'
-    alias(libs.plugins.jetbrains.kotlin.android)
-}
+apply plugin: 'com.android.library'
+apply plugin: 'com.vanniktech.maven.publish'
+apply plugin: 'com.diffplug.spotless'
+apply plugin: 'kotlin-android'
 
 spotless {
     kotlin {
@@ -37,8 +35,8 @@ android {
     }
 
     compileOptions {
-        sourceCompatibility = JavaVersion.VERSION_11
-        targetCompatibility = JavaVersion.VERSION_11
+        sourceCompatibility = JavaVersion.VERSION_17
+        targetCompatibility = JavaVersion.VERSION_17
     }
 
     sourceSets {
@@ -50,7 +48,7 @@ android {
         }
     }
     kotlinOptions {
-        jvmTarget = "11"
+        jvmTarget = "17"
         freeCompilerArgs += ["-Xjvm-default=all"]
     }
 }
@@ -60,6 +58,7 @@ task copyTestRes(type: Exec) {
 }
 
 dependencies {
+    api project(':executorch_java')
     implementation 'com.facebook.fbjni:fbjni:0.7.0'
     implementation 'com.facebook.soloader:nativeloader:0.10.5'
     implementation libs.core.ktx

extension/android/executorch_android/src/main/java/org/pytorch/executorch/AndroidLogger.kt

@@ -0,0 +1,35 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+package org.pytorch.executorch
+
+import android.util.Log as AndroidLog
+
+/**
+ * Android-specific [Logger] implementation that delegates to [android.util.Log].
+ *
+ * Discovered automatically via [java.util.ServiceLoader] when the executorch-android AAR is on the
+ * classpath.
+ */
+class AndroidLogger : Logger {
+  override fun e(tag: String, msg: String) {
+    AndroidLog.e(tag, msg)
+  }
+
+  override fun w(tag: String, msg: String) {
+    AndroidLog.w(tag, msg)
+  }
+
+  override fun i(tag: String, msg: String) {
+    AndroidLog.i(tag, msg)
+  }
+
+  override fun d(tag: String, msg: String) {
+    AndroidLog.d(tag, msg)
+  }
+}

extension/android/executorch_android/src/main/resources/META-INF/services/org.pytorch.executorch.Logger

@@ -0,0 +1 @@
+org.pytorch.executorch.AndroidLogger

extension/android/gradle/libs.versions.toml

@@ -15,3 +15,4 @@ junit = { module = "junit:junit", version.ref = "junit" }
 core-ktx = { group = "androidx.core", name = "core-ktx", version.ref = "core-ktx" }
 [plugins]
 jetbrains-kotlin-android = { id = "org.jetbrains.kotlin.android", version.ref = "kotlin" }
+jetbrains-kotlin-jvm = { id = "org.jetbrains.kotlin.jvm", version.ref = "kotlin" }

extension/android/jni/jni_layer.cpp

@@ -477,7 +477,7 @@ class ExecuTorchJni : public facebook::jni::HybridClass<ExecuTorchJni> {
 
     return ret;
 #else
-    return facebook::jni::JArrayClass<String>::newArray(0);
+    return facebook::jni::JArrayClass<jstring>::newArray(0);
 #endif
   }
 

extension/android/jni/log.cpp

@@ -66,4 +66,34 @@ void access_log_buffer(std::function<void(std::vector<log_entry>&)> accessor) {
 
 } // namespace executorch::extension
 
+#else
+
+#include <cstdio>
+
+namespace executorch::extension {
+
+void access_log_buffer(std::function<void(std::vector<log_entry>&)> accessor) {
+  // No-op for non-Android
+  (void)accessor;
+}
+
+} // namespace executorch::extension
+
+void et_pal_emit_log_message(
+    et_timestamp_t timestamp,
+    et_pal_log_level_t level,
+    const char* filename,
+    const char* function,
+    size_t line,
+    const char* message,
+    size_t length) {
+  (void)timestamp;
+  (void)filename;
+  (void)function;
+  (void)line;
+  (void)length;
+  // Fallback console log for JVM desktop
+  fprintf(stderr, "[ExecuTorch JNI %c] %s\n", level, message);
+}
+
 #endif

extension/android/settings.gradle

@@ -21,4 +21,17 @@ plugins {
 
 rootProject.name = 'executorch'
 
-include('executorch_android')
+// Shared platform-neutral API module (no android.* dependency)
+include(':executorch_java')
+project(':executorch_java').projectDir = new File(rootDir, '../java')
+
+// Android module — only included when Android SDK is available
+if (System.getenv("ANDROID_HOME") != null || System.getenv("ANDROID_SDK_ROOT") != null || new java.io.File(rootDir, "local.properties").exists()) {
+    include('executorch_android')
+} else {
+    logger.warn("WARNING: ANDROID_HOME is not set, skipping Android subproject.")
+}
+
+// Desktop JVM module
+include(':executorch_jvm')
+project(':executorch_jvm').projectDir = new File(rootDir, '../jvm')