Added additional builder method receiving arguments for using jsc or hermes to correctly decide which DSO to load at app startup.

ReactAndroid/src/main/java/com/facebook/react/JSInterpreter.java

@@ -0,0 +1,12 @@
+package com.facebook.react;
+
+/**
+ * An enum that specifies the JS Engine to be used in the app
+ * Old Logic uses the legacy code
+ * JSC/HERMES loads the respective engine using the revamped logic
+ */
+public enum JSInterpreter {
+  OLD_LOGIC,
+  JSC,
+  HERMES
+}

ReactAndroid/src/main/java/com/facebook/react/ReactInstanceManagerBuilder.java

@@ -66,6 +66,7 @@ public class ReactInstanceManagerBuilder {
   private @Nullable Map<String, RequestHandler> mCustomPackagerCommandHandlers;
   private @Nullable ReactPackageTurboModuleManagerDelegate.Builder mTMMDelegateBuilder;
   private @Nullable SurfaceDelegateFactory mSurfaceDelegateFactory;
+  private JSInterpreter jsInterpreter = JSInterpreter.OLD_LOGIC;
 
   /* package protected */ ReactInstanceManagerBuilder() {}
 
@@ -125,6 +126,31 @@ public ReactInstanceManagerBuilder setJSBundleLoader(JSBundleLoader jsBundleLoad
     return this;
   }
 
+  /**
+   * Sets the jsEngine as JSC or HERMES as per the setJsEngineAsHermes call
+   * Uses the enum {@link JSInterpreter}
+   * @param jsInterpreter
+   */
+  private void setJSEngine(JSInterpreter jsInterpreter){
+    this.jsInterpreter = jsInterpreter;
+  }
+
+  /**
+   * Utility setter to set the required JSEngine as HERMES or JSC
+   * Defaults to OLD_LOGIC if not called by the host app
+   * @param hermesEnabled
+   * hermesEnabled = true sets the JS Engine as HERMES and JSC otherwise
+   */
+  public ReactInstanceManagerBuilder setJsEngineAsHermes(boolean hermesEnabled){
+    if(hermesEnabled){
+      setJSEngine(JSInterpreter.HERMES);
+    }
+    else{
+      setJSEngine(JSInterpreter.JSC);
+    }
+    return this;
+  }
+
   /**
    * Path to your app's main module on Metro. This is used when reloading JS during development. All
    * paths are relative to the root folder the packager is serving files from. Examples: {@code
@@ -344,42 +370,36 @@ public ReactInstanceManager build() {
   }
 
   private JavaScriptExecutorFactory getDefaultJSExecutorFactory(
-      String appName, String deviceName, Context applicationContext) {
-    try {
-      // If JSC is included, use it as normal
-      initializeSoLoaderIfNecessary(applicationContext);
-      JSCExecutor.loadLibrary();
-      return new JSCExecutorFactory(appName, deviceName);
-    } catch (UnsatisfiedLinkError jscE) {
-      // https://github.com/facebook/hermes/issues/78 shows that
-      // people who aren't trying to use Hermes are having issues.
-      // https://github.com/facebook/react-native/issues/25923#issuecomment-554295179
-      // includes the actual JSC error in at least one case.
-      //
-      // So, if "__cxa_bad_typeid" shows up in the jscE exception
-      // message, then we will assume that's the failure and just
-      // throw now.
-
-      if (jscE.getMessage().contains("__cxa_bad_typeid")) {
-        throw jscE;
-      }
-
-      // Otherwise use Hermes
+    String appName, String deviceName, Context applicationContext) {
+
+    // Relying solely on try catch block and loading jsc even when
+    // project is using hermes can lead to launch-time crashes especially in
+    // monorepo architectures and hybrid apps using both native android
+    // and react native.
+    // So we can use the value of enableHermes received by the constructor
+    // to decide which library to load at launch
+
+    // if nothing is specified, use old loading method
+    // else load the required engine
+    if (jsInterpreter == JSInterpreter.OLD_LOGIC) {
       try {
+        // If JSC is included, use it as normal
+        initializeSoLoaderIfNecessary(applicationContext);
+        JSCExecutor.loadLibrary();
+        return new JSCExecutorFactory(appName, deviceName);
+      } catch (UnsatisfiedLinkError jscE) {
+        if (jscE.getMessage().contains("__cxa_bad_typeid")) {
+          throw jscE;
+        }
         HermesExecutor.loadLibrary();
         return new HermesExecutorFactory();
-      } catch (UnsatisfiedLinkError hermesE) {
-        // If we get here, either this is a JSC build, and of course
-        // Hermes failed (since it's not in the APK), or it's a Hermes
-        // build, and Hermes had a problem.
-
-        // We suspect this is a JSC issue (it's the default), so we
-        // will throw that exception, but we will print hermesE first,
-        // since it could be a Hermes issue and we don't want to
-        // swallow that.
-        hermesE.printStackTrace();
-        throw jscE;
       }
+    } else if (jsInterpreter == JSInterpreter.HERMES) {
+      HermesExecutor.loadLibrary();
+      return new HermesExecutorFactory();
+    } else {
+      JSCExecutor.loadLibrary();
+      return new JSCExecutorFactory(appName, deviceName);
     }
   }
 }