I am getting      Exception in thread "main" java.lang.NullPointerException       at deneme2.MainFrame.(MainFrame.java:43)       at deneme2.deneme2.main(deneme2.java:88)   C:\Users\Melih\AppData\Local\NetBeans\Cache\8.1\executor-snippets\run.xml:53: Java returned: 1   BUILD FAILED (total time: 1 second)   I have two classes one for the frame and the other one is for the code, i have done most part of it so far but however i am getting this error. however on my deneme2 class if i remove the MainFrame frame = new MainFrame(); it seems to work.   This is my denem2 class  public class deneme2 extends JFrame {  public static interface MessageOutput {      void appendMessage(String message); }  private MessageOutput msgOutput = new MessageOutput() {     @Override     public void appendMessage(String message) {         System.out.println(message);     } };  public void setMessageOutput(MessageOutput value) {     msgOutput = value; }  private Node front, rear; private int currentSize;  private class Node {      int data;     Node next; }  public deneme2() {     front = null;     rear = null;     currentSize = 0; }  public boolean isEmpty() {     return (currentSize == 0); }  public int dequeue() {     int data = front.data;     front = front.next;     if (isEmpty()) {         rear = null;     }     currentSize--;     msgOutput.appendMessage(data + " removed from the queue");     return data; }  public void enqueue(int data) {     Node oldRear = rear;     rear = new Node();     rear.data = data;     rear.next = null;     if (isEmpty()) {         front = rear;     } else {         oldRear.next = rear;     }     currentSize++;     System.out.println(data + " added to the queue"); }  public static void main(String a[]) throws FileNotFoundException {    MainFrame frame = new MainFrame();    queue.setMessageOutput(frame);     Scanner s = new Scanner(new File("list.txt"));     deneme2 queue = new deneme2();     while (s.hasNext()) {         queue.enqueue(s.nextInt());     }     s.close();     queue.dequeue(); }}   And this is my MainFrame class  public class MainFrame extends JFrame implements deneme2.MessageOutput { private JTextArea txt1; @Override public void appendMessage(String message) {     txt1.append(message); }  public MainFrame() {       JFrame frame = new JFrame();     JButton b1 = new JButton("Load Up the Que");     JButton b2 = new JButton("Add to the Que");     JTextArea txt2 = new JTextArea();      txt1.setEditable(false);      b1.setBounds(50, 100, 180, 100);     b2.setBounds(50, 300, 180, 100);     txt1.setBounds(600, 100, 300, 600);     txt2.setBounds(300, 300, 180, 100);      frame.add(b1);     frame.add(b2);     frame.add(txt1);     frame.add(txt2);     frame.setLayout(null);     frame.setSize(1000, 1500);     frame.setVisible(true);     frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);  }}
129
What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?
23909
Looking for reviewers to suggest optimization and improvements, and to evaluate coding practices.  final class Variables {     private final int x;     private final int y;      Variables(int x2, int y2) {         this.x = x2;         this.y = y2;     }      public int getX() {         return x;     }      public int getY() {         return y;     }      @Override public String toString()  {          return "x = " + x + " y = " + y;     } }  public final class FindMissing {      private FindMissing() {};      /**  * Takes an input a sorted array with two variables that repeat in the  * range. Remaining variable are consecutive. and returns two variables that repeats  *   * eg: for a range of 1,2,3,4, a valid input is [1, 4], [1, 3] etc.  *   * @param a : the sorted array.  */ /*  * Why is start needed ?  * If start is not given then if a1 is empty how do we know if missing numbers were  * [1, 2] or [4, 5] ??.   */ public static Variables sortedConsecutiveTwoMissing (int[] a, int startOfRange) {     if (a == null) throw new NullPointerException("a1 cannot be null. ");      int low = startOfRange;     // calculating the highest value of the range. it needs to be 2 more than length since all elememts are consecutive.     int high = startOfRange + (a.length - 1) + 2;      int i = 0;     boolean foundX = false;     int x = 0;       while (i &lt; a.length) {         if (a[i] != low) {             if (foundX) {                 return new Variables(x, low);             } else {                 x = low;                 foundX = true;             }         } else {             i++;         }         low++;     }      return new Variables(x, high);  }  public static void main(String[] args) {         // unsortedConsecutiveTwoMissing         int[] a6 = {1, 4};         System.out.println("Expected 2 and 3, Actual " + sortedConsecutiveTwoMissing(a6, 1));         // unsortedConsecutiveTwoMissing         int[] a7 = {-4, -1};         System.out.println("Expected -3 and -2, Actual " + sortedConsecutiveTwoMissing(a7, -4));         int[] a8 = {-4, -3, -2, -1};         System.out.println("Expected 0 and 1, Actual " + sortedConsecutiveTwoMissing(a8, -4));         int[] a9 = {5};         System.out.println("Expected 4 and 6, Actual " + sortedConsecutiveTwoMissing(a9, 4));         }      }
100243
My full error:  Java HotSpot(TM) 64-Bit Server VM warning: Using incremental CMS is deprecated and will likely be removed in a future release Error: Could not find or load main class net.minecraft.client.main.Main  I just installed Minecraft 1.8.9 on OSX El Capitan and tried to play offline since my wifi connection has some issues, and I ran into the error above.  Here is the log link:   Do you have any idea how to fix this?
18133
This may seem like a programming 101 question and I had thought I knew the answer but now find myself needing to double check. In this piece of code below, will the exception thrown in the first catch block then be caught by the general Exception catch block below?  try {   // Do something } catch(IOException e) {   throw new ApplicationException("Problem connecting to server"); } catch(Exception e) {   // Will the ApplicationException be caught here? }   I always thought the answer would be no, but now I have some odd behaviour that could be caused by this. The answer is probably the same for most languages but I'm working in Java.
109679
I have the following code:      public class OrderRequestCreationEmails {     public static void sendMail()     {          Messaging.reserveSingleEmailCapacity(2);         Messaging.SingleEmailMessage mail = new Messaging.SingleEmailMessage();         String[] toAddresses = new String[] {'dgriff@varonis.com'};           mail.setToAddresses(toAddresses);          mail.setReplyTo('dgriff@varonis.com');          mail.setSenderDisplayName('Mail Test');          mail.setSubject('Success! Mail Sent');          mail.setBccSender(false);         mail.setPlainTextBody('BODY');          Messaging.sendEmail(new Messaging.SingleEmailMessage[] { mail });     } }   I tried to call this function from a test as such: (I know its not an actual test, its just to see if I receive a mail).  @isTest private class CreationEmailsTest {     @isTest private static void sendMailTest() {         OrderRequestCreationEmails.sendMail();     } }   And I haven't received the mail, no idea why?  It's an example I took from the salesforce developer guide. couldn't find any answers online...  FYI - deliverability in the sandbox is turned on, and test deliverability works
61737
I would like to use Class.newInstance() but the class I am instantiating does not have a nullary constructor. Therefore I need to be able to pass in constructor arguments. Is there a way to do this?
7315
Recently, apps that are fine an hour ago now crash when I open them. The crash report message seems to be caused by a null pointer exception (NPE) in com.google.android.trichromelibrary. Apps affected for me:  Gmail Dashlane  Is it just me, or is there actually something wrong with the library? How can I fix these affected apps? Crash report: *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** Build fingerprint: 'Xiaomi/polaris/polaris:10/QKQ1.190828.002/20.9.4:user/release-keys' Revision: '0' ABI: 'arm64' Timestamp: ... pid: ..., tid: ..., name: com.dashlane &gt;&gt;&gt; com.dashlane &lt;&lt;&lt; uid: ... signal 11 (SIGSEGV), code 1 (SEGV_MAPERR), fault addr 0x0 Cause: null pointer dereference          ...  backtrace:     #00 pc 00000000038621f0 /data/app/ com.google.android.trichromelibrary 438909034-YaxP9ttrIDcQBfleP5vm7Q==/base.apk! libmonochrome_64.so (offset 0x646000) (BuildId: ... )  (click  for the screenshot of the bug report)
16225
Why does it (apparently) make a difference whether I pass null as an argument directly, or pass an Object that I assigned the value null?  Object testVal = null; test.foo(testVal);    // dispatched to foo(Object) // test.foo(null);    // compilation problem -&gt; "The method foo(String) is ambiguous"     public void foo(String arg) { // More-specific     System.out.println("foo(String)"); }  public void foo(Object arg) { // Generic     System.out.println("foo(Object)"); }   In other words, why is the (commented-out) second call to foo(...) not dispatched to foo(Object)?  Update: I use Java 1.6. I could compile Hemal's code without problems, but mine still doesn't compile. The only difference I see is that Hemal's methods are static while mine are not. But I really don't see why this should make a difference...?  Update 2: Solved. I had another method foo(Runnable) in my class, so the dispatcher couldn't unambiguously select the single most specific method. (See my comment in Hemal's second answer.) Thanks everyone for your help.
110820
I'm currently making a callout to a 3rd party vendor and I'm getting a huge response. What is currently messing me up is this section:   "MessageSeq":13,"Description":"config file: config-qa1.txt\"","MessageTS":"2014-02-17T14:46:58","MessageLevel":4,"IsSystemMessage":false   As you can see here, the portion at the end of the Description value is ended with backslash double quote. If I attempt to parse this via the JSONParser I get an exception. Does anyone have an recommendations on how to resolve this?  Exception Message:  System.JSONException: Unexpected character ('"' (code 34)): was expecting comma to separate OBJECT entries at [line:1, column:3699]  Updated with sample Code   public class ResponseWrapper{     // fields from JSON to auto map     public Integer messageSeq;     public String Description;     public String messageTS;     public Integer messageLevel;     public Boolean isSystemMessage;     // parsing fields     private ResponseWrapper theResponse;     private JSONParser parser;      public void parse(String jsonString){         parser = JSON.createParser(jsonString);         parseJSON();     }      private void parseJSON(){            while (parser.nextToken() != null) {             if (parser.getCurrentToken() == JSONToken.START_OBJECT) {                 theResponse = (ResponseWrapper)parser.readValueAs(ResponseWrapper.class);                            }         }     } }  String responseString = '{"MessageSeq":13,"Description":"config file: config-qa1.txt\"","MessageTS":"2014-02-17T14:46:58","MessageLevel":4,"IsSystemMessage":false}'; system.debug('\n\nBEFORE\n' + responseString); ****Place code in here to test such as ReplaceALL*** ResponseWrapper parser = new ResponseWrapper(); parser.parse(responseString);
110175
I am receiving an error stated above on line 26**(listAccount1)**, can anyone guide me on how to solve it?  public class FRB_UpdateExceptionsforBatch {    public static void FRB_Exceptions(){    string FRBRecordTypeID = utility.getFRBProfileNameLabel();       List&lt;Account&gt; lstAccount = new List&lt;Account&gt;();         List&lt;Account&gt; lstAccount1 = new List&lt;Account&gt;();         List&lt;Account&gt; lstAccount2 = new List&lt;Account&gt;();         List&lt;Account&gt; lstAccount3 = new List&lt;Account&gt;();    lstAccount = [Select id,FRB_Firm_Check__c,Number_of_Exception__c,Number_of_exceptions_under_4_6_bucket__c,Number_of_exceptions_under_7_10_bucket__c,Number_of_exceptions_under_11_19_bucket__c,(select id,Account_Standing__c from Process_Adherence_Monitoring__r  where Status__C != 'Closed' AND  recordtypeId =: FRBRecordTypeID AND Account_Standing__c = '0-3 Days (Green - New Exception)' ) FROM Account WHERE FRB_Firm_Check__c = TRUE];     if(lstAccount.size()&gt;0){           for( Account acc : lstAccount )           {               List&lt;Process_Adherence_Monitoring__c&gt; lstCont = acc.Process_Adherence_Monitoring__r;                acc.Number_of_Exception__c = lstCont.size();               acc.FRB_Firm_Check__c = true;           }            update lstAccount;     }         //To update 4-6 bucket      lstAccount1 = [select Id, Name,FRB_Firm_Check__c, Number_of_exceptions_under_4_6_bucket__c,(select id,Account_Standing__c from Process_Adherence_Monitoring__r  where Status__C != 'Closed' AND  recordtypeId =: FRBRecordTypeID AND Account_Standing__c = '4-6 Days (Yellow - Outside Correction Timeframe)' ) from Account where FRB_Firm_Check__c = TRUE];        if(lstAccount1.size()&gt;0){           for( Account acc : lstAccount1 )           {               List&lt;Process_Adherence_Monitoring__c&gt; lstCont1 = acc.Process_Adherence_Monitoring__r;                              acc.Number_of_exceptions_under_4_6_bucket__c= lstCont1.size();               acc.FRB_Firm_Check__c = true;           }            update lstAccount1 ;       }         //To update 6-11 bucket         lstAccount2 =  [select Id, Name,FRB_Firm_Check__c, Number_of_exceptions_under_7_10_bucket__c,(select id,Account_Standing__c from Process_Adherence_Monitoring__r  where Status__C != 'Closed' AND  recordtypeId =: FRBRecordTypeID AND Account_Standing__c = '7-10 Days (Orange - Approaching Critical Timeframe)' ) from Account where FRB_Firm_Check__c = TRUE];        if(lstAccount2.size()&gt;0){           for( Account acc : lstAccount2 )           {               List&lt;Process_Adherence_Monitoring__c&gt; lstCont2 = acc.Process_Adherence_Monitoring__r;                acc.Number_of_exceptions_under_7_10_bucket__c= lstCont2.size();               acc.FRB_Firm_Check__c = true;           }           update lstAccount2 ;       }        //To update 11 bucket            lstAccount3 =  [select Id, Name,FRB_Firm_Check__c, Number_of_exceptions_under_11_19_bucket__c,(select id,Account_Standing__c from Process_Adherence_Monitoring__r  where Status__C != 'Closed' AND  recordtypeId =: FRBRecordTypeID AND Account_Standing__c = '11-19 Days (Red - Immediate Correction Required)' ) from Account where FRB_Firm_Check__c = TRUE];        if(lstAccount3.size()&gt;0){           for( Account acc : lstAccount3 )           {               List&lt;Process_Adherence_Monitoring__c&gt; lstCont3 = acc.Process_Adherence_Monitoring__r;                acc.Number_of_exceptions_under_11_19_bucket__c= lstCont3.size();               acc.FRB_Firm_Check__c = true;           }                              update lstAccount3 ;       }      }   }
46114
First of all, I swear this is not homework, it's a question I was asked in an interview. I think I made a mess of it (though I did realise the solution requires recursion). Here is the question:  Implement the count() method which returns the number of nodes in a tree. If a node doesn't have either a left or right child, the relevant getXXChild() method will return null  class Tree {    Tree getRightChild() {     // Assume this is already implemented   }    Tree getLeftChild() {     // Assume this is already implemented   }    int count() {     // Implement me   } }   My reason for asking the question is simply curious to see the correct solution, and thereby measure how bad mine was.  Cheers, Tony
112781
This is the error I get when I run my web application in an instance of the Tomcat servlet container started by NetBeans. To fix this I even changed the heap size in netbeans.conf, but still it shows the same error. How can I keep this from happening?   HTTP Status 500 -   --------------------------------------------------------------------------------  type Exception report  message   description The server encountered an internal error () that prevented it from fulfilling this request.  exception   javax.servlet.ServletException: Servlet execution threw an exception     org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:362)   root cause   java.lang.OutOfMemoryError: Java heap space  note The full stack trace of the root cause is available in the Apache Tomcat/5.5.9 logs.
40009
I have the following code that shows either a bug or a misunderstanding on my part.  I sent the same list, but modified over an ObjectOutputStream.  Once as [0] and other as [1].  But when I read it, I get [0] twice.  I think this is caused by the fact that I am sending over the same object and ObjectOutputStream must be caching them somehow.  Is this work as it should, or should I file a bug?   import java.io.*; import java.net.*; import java.util.*;  public class OOS {      public static void main(String[] args) throws Exception {         Thread t1 = new Thread(new Runnable() {             public void run() {                 try {                     ServerSocket ss = new ServerSocket(12344);                     Socket s= ss.accept();                      ObjectOutputStream oos = new ObjectOutputStream(s.getOutputStream());                     List same = new ArrayList();                     same.add(0);                     oos.writeObject(same);                     same.clear();                     same.add(1);                     oos.writeObject(same);                  } catch(Exception e) {                     e.printStackTrace();                 }             }         });         t1.start();          Socket s = new Socket("localhost", 12344);         ObjectInputStream ois = new ObjectInputStream(s.getInputStream());          // outputs [0] as expected         System.out.println(ois.readObject());          // outputs [0], but expected [1]         System.out.println(ois.readObject());         System.exit(0);     } }
116653
I have this:  If String.IsNullOrEmpty(editTransactionRow.pay_id.ToString()) = False Then     stTransactionPaymentID = editTransactionRow.pay_id 'Check for null value End If   Now, when editTransactionRow.pay_id is Null Visual Basic throws an exception. Is there something wrong with this code?
81002
When a Java VM crashes with an EXCEPTION_ACCESS_VIOLATION and produces an hs_err_pidXXX.log file, what does that indicate? The error itself is basically a null pointer exception. Is it always caused by a bug in the JVM, or are there other causes like malfunctioning hardware or software conflicts?  Edit: there is a native component, this is an SWT application on win32.
101821
while making a call from php i am getting the error      Attempt to de-reference a null object Class.Demo.Insert:   What is problem in my webservice?  global class Ctest{     global class RequestClass{         webservice String accName;     }      webservice static void   cInsert(RequestClass req){         Account a1 = new Account();         a1.Name = req.accName;         insert a1;     } }   And Our Php Code Is  require_once('salesforceAPI/soapclient/SforceEnterpriseClient.php'); require_once('salesforceAPI/soapclient/SforceHeaderOptions.php');  $sfdc = new SforceEnterpriseClient(); $SoapClient = $sfdc-&gt;createConnection('enterprise.wsdl.xml');  $loginResult = false;  $loginResult = $sfdc-&gt;login(USER, PASSWORD . SECURITY_KEY);  $parsedURL = parse_url($sfdc-&gt;getLocation()); define("_SFDC_SERVER_", substr($parsedURL['host'], 0, strpos($parsedURL['host'], '.'))); define("_WS_NAME_", 'salesforceAPI/Ctest'); define("_WS_WSDL_", _WS_NAME_ . '.xml'); define("_WS_ENDPOINT_", 'https://' . _SFDC_SERVER_ . '.salesforce.com/services/wsdl/class/' . _WS_NAME_); define("_WS_NAMESPACE_", 'http://soap.sforce.com/schemas/class/' . _WS_NAME_);  $client = new SoapClient(_WS_WSDL_); $sforce_header = new SoapHeader(_WS_NAMESPACE_, "SessionHeader", array("sessionId" =&gt; $sfdc-&gt;getSessionId())); $client-&gt;__setSoapHeaders(array($sforce_header));  $method = $client-&gt;__getFunctions();  $wsParams = array('accName' =&gt; 'XXXXXXX');  $client-&gt;cInsert($wsParams)
9051
Check out the below program.   try {     for (String data : Files.readAllLines(Paths.get("D:/sample.txt"))){         String[] de = data.split(";");         System.out.println("Length = " + de.length);     } } catch (IOException e) {     e.printStackTrace(); }   Sample.txt:   1;2;3;4 A;B;; a;b;c;   Output:   Length = 4 Length = 2 Length = 3   Why second and third output is giving 2 and 3 instead of 4. In sample.txt file, condition  for 2nd and 3rd line is should give newline(\n or enter) immediately after giving delimiter for the third field. Can anyone help me how to get length as 4 for 2nd and 3rd line without changing the condition of the sample.txt file and how to print the values of de[2] (throws  ArrayIndexOutOfBoundsException)?