Android Emulator: SyntaxErorr ' Attempt to redefine Property 'Content - Type'

[nicolabortignon]

Description

Unfortunately I have no idea where to start to fix this.
If I select Remote JS Debugging, the error disappear and the app starts and works normally.
I don't have this problem while running on iOS

Reproduction

This happens when I try to run react-native run-android on this repo

Solution

Additional Information

• React Native version:
  react-native-cli: 2.0.1
  react-native: 0.40.0
• Platform:
  android 23.0.1
• Operating System:
  OSX Sierra

[ericvicenti]

Hmm, all I can suggest here is process of elimination. Does this happen when you debug a blank project in your environment? Does this happen just on emulator or also on device? Have you tried both genymotion and android emulator?

[nicolabortignon]

This is the log from logcat, quite not informative, anything else I can do?

02-27 12:31:10.666  1531  1895 W InputMethodManagerService: Window already focused, ignoring focus gain of: com.android.internal.view.IInputMethodClient$Stub$Proxy@c3700b7 attribute=null, token = android.os.BinderProxy@acf71f4
02-27 12:31:10.669  2599  2617 W unknown:ViewManagerPropertyUpdater: Could not find generated setter for class com.facebook.react.views.picker.ReactDropdownPickerManager
02-27 12:31:10.670  2599  2617 W unknown:ViewManagerPropertyUpdater: Could not find generated setter for class com.facebook.react.views.scroll.ReactHorizontalScrollViewManager
02-27 12:31:10.672  2599  2617 W unknown:ViewManagerPropertyUpdater: Could not find generated setter for class com.facebook.react.views.image.ReactImageManager
02-27 12:31:10.678  2599  2617 W unknown:ViewManagerPropertyUpdater: Could not find generated setter for class com.facebook.react.views.modal.ReactModalHostManager
02-27 12:31:10.679  2599  2617 W unknown:ViewManagerPropertyUpdater: Could not find generated setter for class com.facebook.react.views.modal.ModalHostShadowNode
02-27 12:31:10.679  2599  2617 W unknown:ViewManagerPropertyUpdater: Could not find generated setter for class com.facebook.react.views.progressbar.ReactProgressBarViewManager
02-27 12:31:10.680  2599  2617 W unknown:ViewManagerPropertyUpdater: Could not find generated setter for class com.facebook.react.views.progressbar.ProgressBarShadowNode
02-27 12:31:10.680  2599  2617 W unknown:ViewManagerPropertyUpdater: Could not find generated setter for class com.facebook.react.views.text.ReactRawTextManager
02-27 12:31:10.681  2599  2617 W unknown:ViewManagerPropertyUpdater: Could not find generated setter for class com.facebook.react.views.text.ReactTextShadowNode
02-27 12:31:10.682  2599  2617 W unknown:ViewManagerPropertyUpdater: Could not find generated setter for class com.facebook.react.views.scroll.ReactScrollViewManager
02-27 12:31:10.683  2599  2617 W unknown:ViewManagerPropertyUpdater: Could not find generated setter for class com.facebook.react.views.slider.ReactSliderManager
02-27 12:31:10.684  2599  2617 W unknown:ViewManagerPropertyUpdater: Could not find generated setter for class com.facebook.react.views.slider.ReactSliderManager$ReactSliderShadowNode
02-27 12:31:10.685  2599  2617 W unknown:ViewManagerPropertyUpdater: Could not find generated setter for class com.facebook.react.views.switchview.ReactSwitchManager
02-27 12:31:10.685  2599  2617 W unknown:ViewManagerPropertyUpdater: Could not find generated setter for class com.facebook.react.views.switchview.ReactSwitchManager$ReactSwitchShadowNode
02-27 12:31:10.686  2599  2617 W unknown:ViewManagerPropertyUpdater: Could not find generated setter for class com.facebook.react.views.text.frescosupport.FrescoBasedReactTextInlineImageViewManager
02-27 12:31:10.688  2599  2617 W unknown:ViewManagerPropertyUpdater: Could not find generated setter for class com.facebook.react.views.text.frescosupport.FrescoBasedReactTextInlineImageShadowNode
02-27 12:31:10.693  2599  2617 W unknown:ViewManagerPropertyUpdater: Could not find generated setter for class com.facebook.react.views.textinput.ReactTextInputManager
02-27 12:31:10.696  2599  2617 W unknown:ViewManagerPropertyUpdater: Could not find generated setter for class com.facebook.react.views.textinput.ReactTextInputShadowNode
02-27 12:31:10.702  2599  2617 W unknown:ViewManagerPropertyUpdater: Could not find generated setter for class com.facebook.react.views.text.ReactTextViewManager
02-27 12:31:10.703  2599  2617 W unknown:ViewManagerPropertyUpdater: Could not find generated setter for class com.facebook.react.views.toolbar.ReactToolbarManager
02-27 12:31:10.707  2599  2617 W unknown:ViewManagerPropertyUpdater: Could not find generated setter for class com.facebook.react.views.view.ReactViewManager
02-27 12:31:10.716  2599  2617 W unknown:ViewManagerPropertyUpdater: Could not find generated setter for class com.facebook.react.views.viewpager.ReactViewPagerManager
02-27 12:31:10.717  2599  2617 W unknown:ViewManagerPropertyUpdater: Could not find generated setter for class com.facebook.react.views.text.ReactVirtualTextViewManager
02-27 12:31:10.719  2599  2617 W unknown:ViewManagerPropertyUpdater: Could not find generated setter for class com.facebook.react.views.webview.ReactWebViewManager
02-27 12:31:10.720  2599  2617 W unknown:ViewManagerPropertyUpdater: Could not find generated setter for class com.facebook.react.views.recyclerview.RecyclerViewBackedScrollViewManager
02-27 12:31:10.722  2599  2617 W unknown:ViewManagerPropertyUpdater: Could not find generated setter for class com.facebook.react.views.swiperefresh.SwipeRefreshLayoutManager
02-27 12:31:10.728  2599  2617 W unknown:ViewManagerPropertyUpdater: Could not find generated setter for class com.facebook.reactnative.androidsdk.FBLikeViewManager
02-27 12:31:10.729  2599  2617 W unknown:ViewManagerPropertyUpdater: Could not find generated setter for class com.facebook.reactnative.androidsdk.FBLoginButtonManager
02-27 12:31:10.730  2599  2617 W unknown:ViewManagerPropertyUpdater: Could not find generated setter for class com.facebook.reactnative.androidsdk.FBSendButtonManager
02-27 12:31:10.730  2599  2617 W art     : Before Android 4.1, method boolean com.facebook.share.widget.ShareButtonBase.canShare() would have incorrectly overridden the package-private method in android.widget.TextView
02-27 12:31:10.731  2599  2617 W unknown:ViewManagerPropertyUpdater: Could not find generated setter for class com.facebook.reactnative.androidsdk.FBShareButtonManager
02-27 12:31:10.780  2599  2599 W unknown:React: Packager connection already open, nooping.
02-27 12:31:10.780  2599  2599 W unknown:React: Inspector connection already open, nooping.
02-27 12:31:10.812  1531  1550 W AppOps  : Finishing op nesting under-run: uid 10055 pkg com.rnfashion code 24 time=0 duration=0 nesting=0
02-27 12:31:10.873  2599  2639 E unknown:React: Exception in native call from JS
02-27 12:31:10.873  2599  2639 E unknown:React: com.facebook.react.devsupport.JSException: SyntaxError: Attempted to redefine property 'Content-Type'. (http://10.0.2.2:8081/index.android.bundle?platform=android&dev=true&hot=false&minify=false:70987)
02-27 12:31:10.873  2599  2639 E unknown:React: 	at com.facebook.react.bridge.queue.NativeRunnable.run(Native Method)
02-27 12:31:10.873  2599  2639 E unknown:React: 	at android.os.Handler.handleCallback(Handler.java:739)
02-27 12:31:10.873  2599  2639 E unknown:React: 	at android.os.Handler.dispatchMessage(Handler.java:95)
02-27 12:31:10.873  2599  2639 E unknown:React: 	at com.facebook.react.bridge.queue.MessageQueueThreadHandler.dispatchMessage(MessageQueueThreadHandler.java:31)
02-27 12:31:10.873  2599  2639 E unknown:React: 	at android.os.Looper.loop(Looper.java:148)
02-27 12:31:10.873  2599  2639 E unknown:React: 	at com.facebook.react.bridge.queue.MessageQueueThreadImpl$3.run(MessageQueueThreadImpl.java:196)
02-27 12:31:10.873  2599  2639 E unknown:React: 	at java.lang.Thread.run(Thread.java:818)
02-27 12:31:10.873  2599  2639 E unknown:React: Caused by: com.facebook.jni.CppException: SyntaxError: Attempted to redefine property 'Content-Type'. (http://10.0.2.2:8081/index.android.bundle?platform=android&dev=true&hot=false&minify=false:70987)
02-27 12:31:10.873  2599  2639 E unknown:React: 	... 7 more
02-27 12:31:10.881  2599  2639 E unknown:React: Exception in native call
02-27 12:31:10.881  2599  2639 E unknown:React: java.lang.RuntimeException: Error calling function: RCTDeviceEventEmitter:emit
02-27 12:31:10.881  2599  2639 E unknown:React: 	at com.facebook.react.bridge.queue.NativeRunnable.run(Native Method)
02-27 12:31:10.881  2599  2639 E unknown:React: 	at android.os.Handler.handleCallback(Handler.java:739)
02-27 12:31:10.881  2599  2639 E unknown:React: 	at android.os.Handler.dispatchMessage(Handler.java:95)
02-27 12:31:10.881  2599  2639 E unknown:React: 	at com.facebook.react.bridge.queue.MessageQueueThreadHandler.dispatchMessage(MessageQueueThreadHandler.java:31)
02-27 12:31:10.881  2599  2639 E unknown:React: 	at android.os.Looper.loop(Looper.java:148)
02-27 12:31:10.881  2599  2639 E unknown:React: 	at com.facebook.react.bridge.queue.MessageQueueThreadImpl$3.run(MessageQueueThreadImpl.java:196)
02-27 12:31:10.881  2599  2639 E unknown:React: 	at java.lang.Thread.run(Thread.java:818)
02-27 12:31:10.881  2599  2639 E unknown:React: Caused by: java.lang.RuntimeException: Empty Optional cannot be unwrapped
02-27 12:31:10.881  2599  2639 E unknown:React: 	... 7 more
02-27 12:31:10.886  2599  2639 E unknown:React: Exception in native call
02-27 12:31:10.886  2599  2639 E unknown:React: java.lang.RuntimeException: Error calling function: AppRegistry:runApplication
02-27 12:31:10.886  2599  2639 E unknown:React: 	at com.facebook.react.bridge.queue.NativeRunnable.run(Native Method)
02-27 12:31:10.886  2599  2639 E unknown:React: 	at android.os.Handler.handleCallback(Handler.java:739)
02-27 12:31:10.886  2599  2639 E unknown:React: 	at android.os.Handler.dispatchMessage(Handler.java:95)
02-27 12:31:10.886  2599  2639 E unknown:React: 	at com.facebook.react.bridge.queue.MessageQueueThreadHandler.dispatchMessage(MessageQueueThreadHandler.java:31)
02-27 12:31:10.886  2599  2639 E unknown:React: 	at android.os.Looper.loop(Looper.java:148)
02-27 12:31:10.886  2599  2639 E unknown:React: 	at com.facebook.react.bridge.queue.MessageQueueThreadImpl$3.run(MessageQueueThreadImpl.java:196)
02-27 12:31:10.886  2599  2639 E unknown:React: 	at java.lang.Thread.run(Thread.java:818)
02-27 12:31:10.886  2599  2639 E unknown:React: Caused by: java.lang.RuntimeException: Empty Optional cannot be unwrapped
02-27 12:31:10.886  2599  2639 E unknown:React: 	... 7 more
02-27 12:31:10.889  2599  2639 E unknown:React: Exception in native call
02-27 12:31:10.889  2599  2639 E unknown:React: java.lang.RuntimeException: Error calling function: RCTDeviceEventEmitter:emit
02-27 12:31:10.889  2599  2639 E unknown:React: 	at com.facebook.react.bridge.queue.NativeRunnable.run(Native Method)
02-27 12:31:10.889  2599  2639 E unknown:React: 	at android.os.Handler.handleCallback(Handler.java:739)
02-27 12:31:10.889  2599  2639 E unknown:React: 	at android.os.Handler.dispatchMessage(Handler.java:95)
02-27 12:31:10.889  2599  2639 E unknown:React: 	at com.facebook.react.bridge.queue.MessageQueueThreadHandler.dispatchMessage(MessageQueueThreadHandler.java:31)
02-27 12:31:10.889  2599  2639 E unknown:React: 	at android.os.Looper.loop(Looper.java:148)
02-27 12:31:10.889  2599  2639 E unknown:React: 	at com.facebook.react.bridge.queue.MessageQueueThreadImpl$3.run(MessageQueueThreadImpl.java:196)
02-27 12:31:10.889  2599  2639 E unknown:React: 	at java.lang.Thread.run(Thread.java:818)
02-27 12:31:10.889  2599  2639 E unknown:React: Caused by: java.lang.RuntimeException: Empty Optional cannot be unwrapped
02-27 12:31:10.889  2599  2639 E unknown:React: 	... 7 more

[haloJim]

I have the same issue as you. After checking, this problem does not happen in the ES6 in android because it's supported to redefine in ES6. Check your code (even node_module code) by opening your bundle file and check the corresponding 70915 lines of code to find which 'Content - Type' is redefine.

[nicolabortignon]

That solve the problem, thank you @haloJim

for those having the same error, what i did is:
on the machine when the package is running, head to
http://127.0.0.1:8081/index.android.bundle?platform=android&dev=true&hot=false&minify=false

check the line, most probably you are trying to redefine something that you already did before.