Add ExecuTorchRuntime.java skeleton

extension/android/BUCK

@@ -8,6 +8,7 @@ non_fbcode_target(_kind = fb_android_library,
     srcs = [
         "executorch_android/src/main/java/org/pytorch/executorch/DType.java",
         "executorch_android/src/main/java/org/pytorch/executorch/EValue.java",
+        "executorch_android/src/main/java/org/pytorch/executorch/ExecuTorchRuntime.java",
         "executorch_android/src/main/java/org/pytorch/executorch/MethodMetadata.java",
         "executorch_android/src/main/java/org/pytorch/executorch/Module.java",
         "executorch_android/src/main/java/org/pytorch/executorch/Tensor.java",

extension/android/executorch_android/src/main/java/org/pytorch/executorch/ExecuTorchRuntime.java

@@ -0,0 +1,33 @@
+/*
+ * 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 com.facebook.soloader.nativeloader.NativeLoader;
+import com.facebook.soloader.nativeloader.SystemDelegate;
+
+/** Class for entire ExecuTorch Runtime related functions. */
+public class ExecuTorchRuntime {
+
+  static {
+    if (!NativeLoader.isInitialized()) {
+      NativeLoader.init(new SystemDelegate());
+    }
+    // Loads libexecutorch.so from jniLibs
+    NativeLoader.loadLibrary("executorch");
+  }
+
+  private static final ExecuTorchRuntime sInstance = new ExecuTorchRuntime();
+
+  private ExecuTorchRuntime() {}
+
+  /** Get the runtime instance. */
+  public static ExecuTorchRuntime getRuntime() {
+    return sInstance;
+  }
+}

extension/android/executorch_android/src/main/java/org/pytorch/executorch/Module.java

@@ -11,8 +11,6 @@
 import android.util.Log;
 import com.facebook.jni.HybridData;
 import com.facebook.jni.annotations.DoNotStrip;
-import com.facebook.soloader.nativeloader.NativeLoader;
-import com.facebook.soloader.nativeloader.SystemDelegate;
 import java.io.File;
 import java.util.HashMap;
 import java.util.Map;
@@ -28,14 +26,6 @@
 @Experimental
 public class Module {
 
-  static {
-    if (!NativeLoader.isInitialized()) {
-      NativeLoader.init(new SystemDelegate());
-    }
-    // Loads libexecutorch.so from jniLibs
-    NativeLoader.loadLibrary("executorch");
-  }
-
   /** Load mode for the module. Load the whole file as a buffer. */
   public static final int LOAD_MODE_FILE = 0;
 
@@ -57,6 +47,8 @@ private static native HybridData initHybrid(
       String moduleAbsolutePath, int loadMode, int initHybrid);
 
   private Module(String moduleAbsolutePath, int loadMode, int numThreads) {
+    ExecuTorchRuntime runtime = ExecuTorchRuntime.getRuntime();
+
     mHybridData = initHybrid(moduleAbsolutePath, loadMode, numThreads);
 
     mMethodMetadata = populateMethodMeta();

extension/android/executorch_android/src/main/java/org/pytorch/executorch/extension/llm/LlmModule.java

@@ -10,9 +10,9 @@
 
 import com.facebook.jni.HybridData;
 import com.facebook.jni.annotations.DoNotStrip;
-import com.facebook.soloader.nativeloader.NativeLoader;
-import com.facebook.soloader.nativeloader.SystemDelegate;
 import java.io.File;
+
+import org.pytorch.executorch.ExecuTorchRuntime;
 import org.pytorch.executorch.annotations.Experimental;
 
 /**
@@ -27,13 +27,6 @@ public class LlmModule {
   public static final int MODEL_TYPE_TEXT = 1;
   public static final int MODEL_TYPE_TEXT_VISION = 2;
 
-  static {
-    if (!NativeLoader.isInitialized()) {
-      NativeLoader.init(new SystemDelegate());
-    }
-    NativeLoader.loadLibrary("executorch");
-  }
-
   private final HybridData mHybridData;
   private static final int DEFAULT_SEQ_LEN = 128;
   private static final boolean DEFAULT_ECHO = true;
@@ -48,6 +41,8 @@ private static native HybridData initHybrid(
    */
   public LlmModule(
       int modelType, String modulePath, String tokenizerPath, float temperature, String dataPath) {
+    ExecuTorchRuntime runtime = ExecuTorchRuntime.getRuntime();
+
     File modelFile = new File(modulePath);
     if (!modelFile.canRead() || !modelFile.isFile()) {
       throw new RuntimeException("Cannot load model path " + modulePath);