nullpointerexception

问题 When loading a picture into byte[] in smartphone app sometimes ByteArrayOutputStream gives me nullpointerexception any explanation? Bitmap bm = BitmapFactory.decodeFile(path); System.out.println("BITMAP: "+bm != null); ByteArrayOutputStream buffer = new ByteArrayOutputStream(); bm.compress(CompressFormat.JPEG, 100, buffer); 回答1: Are you sure it's ByteArrayOutputStream that's giving you the NullPointerException? Or is it happening at bm.compress? bm can be null - likely due to you passing in

问题 When loading a picture into byte[] in smartphone app sometimes ByteArrayOutputStream gives me nullpointerexception any explanation? Bitmap bm = BitmapFactory.decodeFile(path); System.out.println("BITMAP: "+bm != null); ByteArrayOutputStream buffer = new ByteArrayOutputStream(); bm.compress(CompressFormat.JPEG, 100, buffer); 回答1: Are you sure it's ByteArrayOutputStream that's giving you the NullPointerException? Or is it happening at bm.compress? bm can be null - likely due to you passing in

问题 Does anyone have a clue what could be causing this? 11-16 16:23:26.745: ERROR/AndroidRuntime(9549): Uncaught handler: thread main exiting due to uncaught exception 11-16 16:23:26.765: ERROR/AndroidRuntime(9549): java.lang.NullPointerException 11-16 16:23:26.765: ERROR/AndroidRuntime(9549): at android.view.ViewGroup.dispatchWindowVisibilityChanged(ViewGroup.java:692) 11-16 16:23:26.765: ERROR/AndroidRuntime(9549): at android.view.ViewGroup.dispatchWindowVisibilityChanged(ViewGroup.java:692) 11

问题 Scala has a weird drawback, that I cannot create a default argument in args . Here is my latest attempt: object Main extends java.lang.Object with ScalaObject with App { override val args:Array[String]=Array(args.toList.headOption.getOrElse("f")) println("args(0) = " + args(0)) } Run the code here: http://ideone.com/B20HBA Exception in thread "main" java.lang.NullPointerException at scala.collection.mutable.ArrayOps$ofRef$.length$extension(ArrayOps.scala:114) at scala.collection.mutable

问题 UPDATE: The same problem occurs even if I remove the call to the FXMLLoader class. The exception is thrown even with an empty start() method. The problem isn't related at all to the directory tree structure. For every JavaFX project I start, I always have the issue of NullPointerException s being thrown at startup. This happens even with the most basic code needed to even show a stage. I can replicate the issue with the following code: Main.java import javafx.application.Application; import

问题 Alright so I'm having a problem with some code that is generating a null pointer exception, meaning that my code is attempting to use a null value where it should be using an object (Straight out of the API). What I'm doing is I have a class called Hotel that has a constructor which assigns a string value to a variable and creates an array of type Room, an object. I know this should be straight forward yet for the life of me I cannot figure this out. I'll try and keep the code as minimalist

问题 I've been doing this homework assignment and I feel like I've tried anything that I could do, but this is just so frustrating. Basically this program is supposed to simulate the admin console of someone who monitors computers labs. There are 3 options at the main menu, and I've got all of them to work except for the "logoff" function. The big issue with this program is that the labs are supposed to be arrays and the ID Numbers that are located at a particular computer station are supposed to

问题 Good morning, I have this error when I try to register or login via my virtual device : E/StorageHelpers: Failed to turn object into JSON java.lang.NullPointerException: Attempt to invoke virtual method 'org.json.JSONObject com.google.firebase.auth.internal.zzm.zzbf()' on a null object reference at com.google.firebase.auth.internal.zzz.zzi(Unknown Source) at com.google.firebase.auth.internal.zzz.zzg(Unknown Source) at com.google.firebase.auth.FirebaseAuth.zza(Unknown Source) at com.google

问题 Is there a way I can tell PHP to throw an exception when I am trying to access a member or method on a null object? E.g.: $x = null; $x->foo = 5; // Null field access $x->bar(); // Null method call Right now, I only get the following errors which are not nice to handle: PHP Notice: Trying to get property of non-object in ... PHP Warning: Creating default object from empty value in ... PHP Fatal error: Call to undefined method stdClass::bar() in ... I would like to have a specific exception

问题 String s = null; s = s + "hai"; System.out.println(s); Output: nullhai Thought this would throw me NPE. What is the fundamental logic behind not throwing NPE while using + (concatenation) throwing NPE while using . 回答1: For , s = s + "hai"; Internally, String.valueOf(null) will be called. That method will convert null to "null" . Byte code : public static void main(java.lang.String[]) throws java.lang.Exception; 0: aconst_null //some code 10: invokestatic #27; //Method java/lang/String