nullpointerexception

问题 When trying to start a google app engine project in eclipse i keep getting an error saying Server App Engine Standard at localhost failed to start(error log below). Has anyone come across this issue before and what was the cause of the issue. WARNING: An illegal reflective access operation has occurred WARNING: Illegal reflective access by com.google.appengine.tools.development.StreamHandlerFactory (file:/C:/Users/AppData/Local/google/ct4j-cloud-sdk/LATEST/google-cloud-sdk/platform/google

问题 When trying to start a google app engine project in eclipse i keep getting an error saying Server App Engine Standard at localhost failed to start(error log below). Has anyone come across this issue before and what was the cause of the issue. WARNING: An illegal reflective access operation has occurred WARNING: Illegal reflective access by com.google.appengine.tools.development.StreamHandlerFactory (file:/C:/Users/AppData/Local/google/ct4j-cloud-sdk/LATEST/google-cloud-sdk/platform/google

问题 When trying to start a google app engine project in eclipse i keep getting an error saying Server App Engine Standard at localhost failed to start(error log below). Has anyone come across this issue before and what was the cause of the issue. WARNING: An illegal reflective access operation has occurred WARNING: Illegal reflective access by com.google.appengine.tools.development.StreamHandlerFactory (file:/C:/Users/AppData/Local/google/ct4j-cloud-sdk/LATEST/google-cloud-sdk/platform/google

问题 I'm still fighting with my issue. I want to use Spring Framework in order to incject dependencies and I have to use Spring boot to integrate both. Unfortunately, in first view autowiring is run correctly, but if I go next Stage, I got still only Null Pointer Exception . Thats main class: @SpringBootApplication(scanBasePackages = "boxingchallenge") public class BoxingChallengeApplication extends Application { public ConfigurableApplicationContext springContext; private Parent root; public

问题 I am trying to implement an array of LinkedHashMap but I don't know if it's possible... For the moment my code looks like as follows : public class LHMap { public static void main(String[] args) { LinkedHashMap<String, Integer>[] map = null; for (int i = 0; i < 5; i++) { map[i] = new LinkedHashMap<String, Integer>(); } map[0].put("a", 0); System.out.println(map[0].get("a")); } } System.out.println(extracted(map)[0].get("a")); returns a "NullPointerException"... Have you got any idea how to

问题 This question already has answers here : What is a NullPointerException, and how do I fix it? (12 answers) Closed 2 years ago . I try to create a ListView which showes my Pojos called "Baustelle". I wrote a Adapter and a ViewHolder as I learned it in school but the difference is that we only did it for the MainActivity in my school. Now i tried to use a Fragment for it but I always get this Error: "Attempt to invoke virtual method 'android.view.View android.view.View.findViewById(int)' on a

问题 I'm using com.google.android.gms:play-services-maps:11.0.2 version of Google Map Service. When trying to call the below, I get the following error: java.lang.NullPointerException: Attempt to invoke virtual method void com.google.android.gms.maps.MapFragment.getMapAsync(com.google.android.gms.maps.OnMapReadyCallback)' on a null object reference Below is my code: @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity

问题 This question already has answers here : What is a NullPointerException, and how do I fix it? (12 answers) Closed 5 years ago . This is the following code. I have to make the array null for a purpose, then when I initialize the array components to 1, it shows null pointer exception. How to handle this? public static void main(String[] args) { double[] a; a=null; if(a==null) for(int i=0;i<12;i++) a[i]=1; } 回答1: You need to create an array object and assign it to the array variable before

问题 This question already has answers here : What is a NullPointerException, and how do I fix it? (12 answers) Closed 2 years ago . I've created an app with a drawer menu that opens a new fragment for each menu option. Within those fragments i'm attempting run several functions. I've parsed an RSS feed, and want to display the information I've parsed on a ListView inside a specific fragment. My main activity navigates to the fragment no problem but gets stuck with a Null Pointer exception. This

问题 i am a beginner . First of all say that I have read previous posts but did not answer. I try to test a audio player,But when I try to run the app, it instantly crashes because of a null object reference. This is Logcat: (this log say: Error is in Line 28 of java code) EXCEPTION: main Process: ir.pluto.mediaplayer, PID: 19100 java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{ir.pluto.mediaplayer/ir.pluto.mediaplayer.MainActivity}: java.lang.NullPointerException: Attempt