nullpointerexception

问题 I am trying to find duplicate words in a string array. Here is my code for the comparison: for ( int j = 0 ; j < wordCount ; j++) { for (int i = wordCount-1 ; i > j ; i--) { if (stringArray[i].compareTo(stringArray[j]) == 0 && i!=j) { //duplicate duplicates++; } } } wordCount -= duplicates; System.out.print("\nNumber of words, not including duplicates: " + wordCount); in the if statement, it says NullPointerException . What does this mean? Is there a better way to do this? I tried simply

问题 I made a game in Java. It works completly fine in Eclipse. I exported it as a Runnable JAR. When double-clicking on it's icon, it doesn't open. So I tried running the JAR from the command line. I get a NullPointerException error, in a line of code that's trying to retrieve an image resource (as I said, it works fine inside Eclipse). This is the line of code where the error happens: ball = new ImageIcon(this.getClass().getResource("sprites/ball.PNG")); I have no idea what's wrong. Here is the

问题 I am facing an issue with NullPointerException. I tried as much as possible but I'm unable to resolve this. I am implementing a POM model(Selenium) for my project. The page: public class VendorsHomePageApp { WebDriver driver; public VendorsHomePageApp(WebDriver driver) { this.driver=driver; } @FindBy(how=How.XPATH,using=".//*[@id='navbarCollapse']/ul[1]/li[1]/a") WebElement dashboardTab; @FindBy(how=How.XPATH,using=".//*[@id='navbarCollapse']/ul[1]/li[2]/a") WebElement tendersTab; @FindBy(how

问题 I am getting NullPointerException while Starting One Fragment From other Fragment. I am trying to call a method in the second Fragment after Starting the Fragment dynamically. Here is my logcat: 05-20 09:58:31.907: E/AndroidRuntime(2585): FATAL EXCEPTION: main 05-20 09:58:31.907: E/AndroidRuntime(2585): java.lang.NullPointerException 05-20 09:58:31.907: E/AndroidRuntime(2585): at com.exercise.FragmentTest.MyFragment3.setImage(MyFragment3.java:22) 05-20 09:58:31.907: E/AndroidRuntime(2585): at

问题 I have many of these calls: (ListView) getView().findViewById(R.id.main_list_view); (TextView) getView().findViewById(R.id.items_no); .... and AndroidStudio tells me that they may procude a NullPointerException : Method invocation getView().findViewById(R.id.main_list_view) may produce java.lang.NullPointerException less... (Ctrl+F1) This inspection analyzes method control and data flow to report possible conditions that are always true or false, expressions whose value is statically proven

问题 I have written an android program to load values to tablerow from web service. But a value comes null so I need do convert it into string. Can some one tell me the method to do it. try{ SoapObject request = service.getRequest(); SoapSerializationEnvelope envelope = service.getEnvelope(request); SoapObject response = service.getResponse(envelope); Log.i("Service Master", response.toString()); int count = response.getPropertyCount(); for (int i = 0; i < count; i++) { SoapObject result =

问题 public class SupplierCalculatorApplet extends JApplet{ ... public void init(){ loadProperties(); ... } ... private void loadProperties() { language = "en-us";//getParameter("Language"); prop = new Properties(); try { URL urlToProps = this.getClass().getResource("config/" + language + ".properties"); prop.load(urlToProps.openStream());//Exception Caught Here } catch (IOException e) { } } Exception is found at the line indicated above. Whether language is a valid properties file or not, I catch

问题 I get certain data like say userName in Activity_1 from a web server. Then i want to use the same data in Activity_2 so i made this userName Public Static and used like this in Activity_2 Activity_1.userName But then when i am in Activity_2 and press Home Button and reopen the application 5 mins later, this Activity_1.userName become Null since that Activity_1 data is destroyed . and I get NullPointerException How to solve this in a simple way. I just gave an example of userName but actually

问题 hi we've been reading xls and xlsx file using apache poi ing our java program, the problem is we are getting null pointer exception with two reasons.. the first 1 is the blank cell which we already solved and the other one is when we are choosing a certain column that doesn't have any record.. our program ask for the path of the excel file then the specific sheet number of the file and the specific column number of the sheet you want to read.. here is the code for reading xls file public void

问题 I am a newbie of android world. I have a problem of the coding. It was just a tiny error buy i dont know it doesnt work even i change others method but the error still the same error. Here the error occur at logcat: java.lang.NullPointerException: Attempt to invoke virtual method 'android.database.Cursor com.example.zellon.surveyapps.DatabaseHelper.getAData()' on a null object reference I just want to select the data in the database to get an id but cant cuz of the error above. I will give a