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.
 #
@@ -13,64 +13,80 @@
 endif()
 
 if(NOT ANDROID)
-  message(FATAL_ERROR "This directory is for Android build only")
-endif()
+  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(EXECUTORCH_ROOT "${CMAKE_CURRENT_SOURCE_DIR}/../..")
-include(${EXECUTORCH_ROOT}/tools/cmake/Utils.cmake)
-set(_common_compile_options
-    $<$<CXX_COMPILER_ID:MSVC>:/wd4996>
-    $<$<NOT:$<CXX_COMPILER_ID:MSVC>>:-Wno-deprecated-declarations -fPIC>
-)
-if(NOT ANDROID_PLATFORM)
-  set(ANDROID_PLATFORM android-30)
-endif()
+  add_library(fbjni SHARED IMPORTED)
+  set_target_properties(
+    fbjni
+    PROPERTIES
+      IMPORTED_LOCATION "${FBJNI_LIBRARY}"
+  )
+  set(_common_compile_options
+      $<$<CXX_COMPILER_ID:MSVC>:/wd4996>
+      $<$<NOT:$<CXX_COMPILER_ID:MSVC>>:-Wno-deprecated-declarations -fPIC>
+  )
+else()
+  set(EXECUTORCH_ROOT "${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()
+  # 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()
 
-set(FBJNI_AAR_URL
-    https://repo1.maven.org/maven2/com/facebook/fbjni/fbjni/${FBJNI_VERSION}/fbjni-${FBJNI_VERSION}.aar
-)
-set(FBJNI_DOWNLOAD_PATH ${CMAKE_CURRENT_BINARY_DIR}/third-party/fbjni/fbjni.aar)
+  set(FBJNI_AAR_URL
+      https://repo1.maven.org/maven2/com/facebook/fbjni/fbjni/${FBJNI_VERSION}/fbjni-${FBJNI_VERSION}.aar
+  )
+  set(FBJNI_DOWNLOAD_PATH ${CMAKE_CURRENT_BINARY_DIR}/third-party/fbjni/fbjni.aar)
 
-if(NOT EXISTS "${FBJNI_DOWNLOAD_PATH}")
-  file(DOWNLOAD "${FBJNI_AAR_URL}" "${FBJNI_DOWNLOAD_PATH}")
-endif()
+  if(NOT EXISTS "${FBJNI_DOWNLOAD_PATH}")
+    file(DOWNLOAD "${FBJNI_AAR_URL}" "${FBJNI_DOWNLOAD_PATH}")
+  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}"
-)
+  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.${ANDROID_ABI}/libfbjni.so"
-)
+  add_custom_target(
+    fbjni_prefab
+    DEPENDS
+      "${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"
+  )
 
-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_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()
 
-executorch_target_link_options_shared_lib(executorch)
+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
@@ -248,4 +264,8 @@
 )
 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/executorch_android/src/main/java/org/pytorch/executorch/Log.kt

@@ -0,0 +1,43 @@
+/*
+ * 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 java.lang.reflect.Method
+
+/**
+ * Platform-agnostic logging helper that forwards logs to android.util.Log when running
+ * on Android, and falls back to standard error console logging when running on desktop JVMs.
+ */
+internal object Log {
+  private var androidLogMethod: Method? = null
+  private var lookupFailed = false
+
+  fun e(tag: String, msg: String) {
+    if (!lookupFailed && androidLogMethod == null) {
+      try {
+        val logClass = Class.forName("android.util.Log")
+        androidLogMethod = logClass.getMethod("e", String::class.java, String::class.java)
+      } catch (e: Exception) {
+        lookupFailed = true
+      }
+    }
+
+    val method = androidLogMethod
+    if (method != null) {
+      try {
+        method.invoke(null, tag, msg)
+        return
+      } catch (e: Exception) {
+        // Fallback to console printing if invocation fails
+      }
+    }
+
+    System.err.println("[$tag] ERROR: $msg")
+  }
+}

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

@@ -8,7 +8,6 @@
 
 package org.pytorch.executorch
 
-import android.util.Log
 import com.facebook.jni.HybridData
 import com.facebook.jni.annotations.DoNotStrip
 import java.nio.Buffer

extension/android/executorch_jvm/build.gradle

@@ -0,0 +1,81 @@
+/*
+ * 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.
+ */
+
+plugins {
+    alias(libs.plugins.jetbrains.kotlin.jvm)
+    id 'java-library'
+    id "com.vanniktech.maven.publish" version "0.31.0"
+}
+
+def execuTorchVersion = System.properties['execuTorchVersion']
+
+java {
+    sourceCompatibility = JavaVersion.VERSION_17
+    targetCompatibility = JavaVersion.VERSION_17
+}
+
+repositories {
+    google()
+    mavenCentral()
+}
+
+dependencies {
+    implementation "org.jetbrains.kotlin:kotlin-stdlib:${libs.versions.kotlin.get()}"
+    implementation "com.facebook.fbjni:fbjni-java-only:${fbjniJavaOnlyVersion}"
+    implementation "com.facebook.soloader:nativeloader:${soLoaderNativeLoaderVersion}"
+}
+
+sourceSets {
+    main {
+        kotlin {
+            srcDirs = ['../executorch_android/src/main/java']
+            exclude '**/androidTest/**'
+            exclude '**/test/**'
+        }
+    }
+}
+
+compileKotlin {
+    kotlinOptions {
+        jvmTarget = "17"
+        freeCompilerArgs += ["-Xjvm-default=all"]
+    }
+}
+
+mavenPublishing {
+    publishToMavenCentral()
+    signAllPublications()
+
+    coordinates("org.pytorch", "executorch-jvm", execuTorchVersion ? execuTorchVersion : "1.2.0-SNAPSHOT")
+
+    pom {
+        name = "ExecuTorch JVM"
+        description = "ExecuTorch Java/Kotlin bindings for standard desktop JVM (Linux, macOS, Windows)"
+        inceptionYear = "2026"
+        url = "https://github.com/pytorch/executorch/"
+        licenses {
+            license {
+                name = "BSD 3-Clause"
+                url = "https://github.com/pytorch/executorch/blob/main/LICENSE"
+                distribution = "https://github.com/pytorch/executorch/blob/main/LICENSE"
+            }
+        }
+        developers {
+            developer {
+                id = "pytorch"
+                name = "pytorch"
+                url = "https://github.com/pytorch/executorch/"
+            }
+        }
+        scm {
+            url = "https://github.com/pytorch/executorch.git"
+            connection = "scm:git:https://github.com/pytorch/executorch"
+            developerConnection = "scm:git:git@github.com:pytorch/executorch.git"
+        }
+    }
+}

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 +21,9 @@ plugins {
 
 rootProject.name = 'executorch'
 
-include('executorch_android')
+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.")
+}
+include('executorch_jvm')