i'm practicing creating apps and i have a problem that i don't understand : why i'm getting this error with this code :       java.lang.NullPointerException: Attempt to invoke virtual method 'java.util.List com.baziremartin.pyramideapp.paquet.getCartes(int)' on a null object reference   the code :    mTestBTN.setOnClickListener(new View.OnClickListener() {             @Override             public void onClick(View v) {                 List&lt;joueur&gt; currentPlayers = new ArrayList&lt;&gt;();                 for(int i = 0; i &lt; allPlayers.size(); i ++){                     currentPlayers.add(new joueur(allPlayers.get(i)));                     currentPlayers.get(i).setHand(paquet1.getCartes(4));                  }             }         });   I've already search and i think it is a reference syntaxe error but i don't understand whats is the good syntax.. (i have try a lot of differents things). Thanks for help i'm beginner in java.
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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?
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Comment on Duplicate Reference: Why would this be marked duplicate when it was asked years prior to the question referenced as a duplicate?  I also believe the question, detail, and response is much better than the referenced question.  I've been a C++ programmer for quite a while but I'm new to Java and new to Eclipse.  I want to use the  to visualize some data I'm working with.  This code is organized like this:  ./com ./com/touchgraph ./com/touchgraph/graphlayout ./com/touchgraph/graphlayout/Edge.java ./com/touchgraph/graphlayout/GLPanel.java ./com/touchgraph/graphlayout/graphelements ./com/touchgraph/graphlayout/graphelements/GESUtils.java ./com/touchgraph/graphlayout/graphelements/GraphEltSet.java ./com/touchgraph/graphlayout/graphelements/ImmutableGraphEltSet.java ./com/touchgraph/graphlayout/graphelements/Locality.java ./com/touchgraph/graphlayout/graphelements/TGForEachEdge.java ./com/touchgraph/graphlayout/graphelements/TGForEachNode.java ./com/touchgraph/graphlayout/graphelements/TGForEachNodePair.java ./com/touchgraph/graphlayout/graphelements/TGNodeQueue.java ./com/touchgraph/graphlayout/graphelements/VisibleLocality.java ./com/touchgraph/graphlayout/GraphLayoutApplet.java ./com/touchgraph/graphlayout/GraphListener.java ./com/touchgraph/graphlayout/interaction ./com/touchgraph/graphlayout/interaction/DragAddUI.java ./com/touchgraph/graphlayout/interaction/DragMultiselectUI.java ./com/touchgraph/graphlayout/interaction/DragNodeUI.java ./com/touchgraph/graphlayout/interaction/GLEditUI.java ./com/touchgraph/graphlayout/interaction/GLNavigateUI.java ./com/touchgraph/graphlayout/interaction/HVRotateDragUI.java ./com/touchgraph/graphlayout/interaction/HVScroll.java ./com/touchgraph/graphlayout/interaction/HyperScroll.java ./com/touchgraph/graphlayout/interaction/LocalityScroll.java ./com/touchgraph/graphlayout/interaction/RotateScroll.java ./com/touchgraph/graphlayout/interaction/TGAbstractClickUI.java ./com/touchgraph/graphlayout/interaction/TGAbstractDragUI.java ./com/touchgraph/graphlayout/interaction/TGAbstractMouseMotionUI.java ./com/touchgraph/graphlayout/interaction/TGAbstractMousePausedUI.java ./com/touchgraph/graphlayout/interaction/TGSelfDeactivatingUI.java ./com/touchgraph/graphlayout/interaction/TGUIManager.java ./com/touchgraph/graphlayout/interaction/TGUserInterface.java ./com/touchgraph/graphlayout/interaction/ZoomScroll.java ./com/touchgraph/graphlayout/LocalityUtils.java ./com/touchgraph/graphlayout/Node.java ./com/touchgraph/graphlayout/TGAbstractLens.java ./com/touchgraph/graphlayout/TGException.java ./com/touchgraph/graphlayout/TGLayout.java ./com/touchgraph/graphlayout/TGLensSet.java ./com/touchgraph/graphlayout/TGPaintListener.java ./com/touchgraph/graphlayout/TGPanel.java ./com/touchgraph/graphlayout/TGPoint2D.java ./com/touchgraph/graphlayout/TGScrollPane.java ./TG-APACHE-LICENSE.txt ./TGGL ReleaseNotes.txt ./TGGraphLayout.html ./TGGraphLayout.jar   How do I add this project in Eclipse and get it compiling and running quickly?
90240
I have the below code:  public class CallOutForGet {      HttpRequest request=new Httprequest(); http http=new http(); request.setEndPoint('https://th-apex-http-callout.herokuapp.com/animals'); request.setmethod('GET');  HttpResponse response=http.send(request);  if(response.getStatusCode()==200){      Map&lt;String,Object&gt; results= (Map&lt;String,Object&gt;)JSON.deserializeUntyped(response.getBody());      List&lt;object&gt; animals=(List&lt;object&gt;)results.get('animals');     System.debug('Received Animals************');     for(object anim:animals){         System.debug(anim);     } }  }   This error at line -  request.setEndPoint('https://th-apex-http-callout.herokuapp.com/animals');  says expecting right parenthesis.
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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));         }      }
110550
For a new project that I'm doing in PHP I've created an SQLMethods class to connect to the database and perform queries. Tonight was the first night that I actually got to test it (I wrote it a week or so ago and forgot about it) and an unexpected error occured: When it was calling my ExecuteQuery() function, it wouldn't use the database I selected in the constructor.  The constructor:      public function SQLMethods() {         $SQLConnection = mysql_connect($SQLDBAddress, $SQLUserName, $SQLPassword);          if (!$SQLConnection) {             die('Could not connect: ' . mysql_error());         }          mysql_select_db($SQLDB, $SQLConnection);     }   The function in question:      public function ExecuteQuery($Query) {         mysql_query($Query, $SQLConnection) or die('Could not perform query: ' . mysql_error());     }   Does anyone see what the issue might be? Does the connection close after the constructor completes?
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what about using "this" with methods in Java? Is it optional or there are situations when one needs to use it obligatory?  The only situation I have encountered is when in the class you invoke a method within a method. But it is optional. Here is a silly example just to show what I mean:  public class Test {      String s;      private String hey() {         return s;     }      public String getS(){         String sm = this.hey();         // here I could just write hey(); without this         return sm;     } }
116296
Anytime I have to handle dates/times in java it makes me sad   I'm trying to parse a string and turn it into a date object to insert in a preparepared statement. I've been trying to get this working but am having no luck. I also get the helpful error message when I go to compile the class.  "Exception in thread "main" java.lang.Error: Unresolved compilation problem:  The method setDate(int, Date) in the type PreparedStatement is not applicable for the arguments (int, Date)"  Eh WTF?  Here is the offending code.  for(int i = 0; i &lt; flights.size(); i++){      String[] details = flight[i].toString().split(":");      DateFormat formatter ;      formatter = new SimpleDateFormat("ddMMyyyy");     Date date = formatter.parse(details[1]);       PreparedStatement pstmt = conn.prepareStatement(insertsql);     pstmt.setString(1, details[0]);     pstmt.setDate(2, date);     pstmt.setString(3, details[2] + "00");     pstmt.setString(4, details[3]);     pstmt.setString(5, details[4]);     pstmt.setString(6, details[5]);     pstmt.setString(7, details[6]);     pstmt.setString(8, details[7]);     pstmt.setString(9, details[8]);     pstmt.executeUpdate();  }
34848
I used to use the implicit call of toString when wanting some debug info about an object, because in case of the object is null it does not throw an Exception.  For instance:    System.out.println("obj: "+obj);   instead of:  System.out.println("obj: "+obj.toString());   Is there any difference apart from the null case? Can the latter case work, when the former does not?  Edit: What exactly is done, in case of the implicit call?
52784
This question appears to have been answered several times on here, but none of the solutions are working for me.  I have an Apex function defined like so:  @RemoteAction global static ActivityWrapper createActivity(Activity__c activity)   And when I call this Javascript function:  Controller.createActivity(     {ForWeek__c: "2014-04-21T08:00:00.000Z",      Notes__c: "sdfsdf",      Type__c: "Referral",      Id: null,      sObjectType: "Activity__c"}, callback);   I always get back this error message:  Visualforce Remoting Exception: Unexpected type for Controller.createActivity(Activity__c)   As far as I know this is all that is required, but I can't get past this.
1064
I know java and would normally put in getter/setter methods. I am interested in doing it in C# with the following code, but it throws a StackOverflow exception. What am I doing wrong?  Calling Code  c.firstName = "a";   Property Code    public String firstName; {     get     {         return firstName;     }     set     {         firstName = value;     } }
110516
I am trying to perform two operations. First I want to increase the size of a GameObject and then delay for 0.1s before returning it back to its original size. However, when I try using StartCoroutine(), it keeps giving me the error :  An object reference is required to access not-static members   even though I made my Delay() function static. Can somebody please tell me what I'm doing wrong?  public static void MoveSelected(int choice) {     GameObject rock1 = GameObject.Find("Rock1");     GameObject paper1 = GameObject.Find("Paper1");     GameObject scissors1 = GameObject.Find("Scissors1");      Vector3 scl;      if (choice == 1)     {         scl = rock1.transform.localScale;         scl.x *= 1.1f;         scl.y *= 1.1f;         rock1.transform.localScale = scl;          StartCoroutine(Delay());          scl.x /= 1.1f;         scl.y /= 1.1f;         rock1.transform.localScale = scl;     }     else if (choice == 2)     {         scl = paper1.transform.localScale;         scl.x *= 1.1f;         scl.y *= 1.1f;         paper1.transform.localScale = scl;          StartCoroutine(Delay());          scl.x /= 1.1f;         scl.y /= 1.1f;         rock1.transform.localScale = scl;     }     else if (choice == 3)     {         scl = scissors1.transform.localScale;         scl.x *= 1.1f;         scl.y *= 1.1f;         scissors1.transform.localScale = scl;          StartCoroutine(Delay());          scl.x /= 1.1f;         scl.y /= 1.1f;         rock1.transform.localScale = scl;     }  }  static IEnumerator Delay() {     yield return new WaitForSeconds(0.1f); }
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I have a lookup to a custom object called Project on my Opportunity object. I am trying to write a trigger that updates an Active, Awarded, and Title on the Project object whenever the Active, Awarded, or Title field is updated on Opportunity based some on more logic that isn't in my code below. This is my first trigger and needing a little help due to a NullPointerException where I try to set Project__r.Active__c = true. Any thoughts?      trigger ProjectFieldsTrigger on Opportunity (before insert, before update) {       //List&lt;Opportunity&gt; opp = [SELECT Name, Active__c, Funded__c, Title__c, Project__r.Name, Project__r.Active__c, Project__r.Awarded__c      //  FROM Opportunity WHERE Id IN :Trigger.New];      for(Opportunity o: Trigger.New){          if(o.Project__c != null){              if(o.Active__c == 'Y'){                 o.Project__r.Active__c = true;             }      }  }
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i am building a app which takes input from user and then search to a remote database(MySql).And then display the retrieved data on VisualForce page.One important note that my app will be distributable.  here is my controller class  public with sharing class Search  {    public String strTag {get;set;}   public String strlocation {get;set;}    public PageReference find() {              return null;   } }   Thanks in advance.  Updated  public with sharing class Search  {   public String strTag {get;set;} public String strlocation {get;set;}   public PageReference find() {             HttpRequest req = new HttpRequest();   HttpResponse res = new HttpResponse();   Http http = new Http();    req.setEndpoint('https://localhost/salesforce/');   req.setMethod('POST');     req.setCompressed(false);   req.setBody('key1=value1&amp;key2=value2');   req.setHeader('Content-Type', 'application/x-www-form-urlencoded');      try {     res = http.send(req);   } catch(System.CalloutException e) {     system.debug('Callout error: '+ e);   }   system.debug(res.getBody());      return null;  } }   I am getting below error now      error message System.CalloutException: Unauthorized endpoint, please check Setup->Security->Remote site settings. endpoint = localhost/salesforce
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I sometimes notice programs that crash on my computer with the error: "pure virtual function call".  How do these programs even compile when an object cannot be created of an abstract class?
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I am trying to start share-point workflow using CSOM(Client side object model) by following means of code. But i got the following error from the line mark in comment. Please help me to figure out this error.     Error :- Cannot invoke method or retrieve property from null   object. Object returned by the following call stack is null.   "GetWorkflowDeploymentService new   Microsoft.SharePoint.WorkflowServices.WorkflowServicesManager() "    public bool StartWorkFlow()  {     string workflowName = "UpdateDealStatus";     // connect to the workflow services via a CSOM client context    var workflowServicesManager = new WorkflowServicesManager(_sharepoint,                  _sharepoint.Web);    // connect to the deployment service    var workflowDeploymentService = workflowServicesManager.GetWorkflowDeploymentService();    // get all installed workflows   var publishedWorkflowDefinitions =    workflowDeploymentService.EnumerateDefinitions(true);             _sharepoint.Load(publishedWorkflowDefinitions);     try    {       _sharepoint.ExecuteQuery();//Error thrown from this line    }    catch (Exception ex)    {      }     // find the first workflow definition    var firstWorkflowDefinition = publishedWorkflowDefinitions.First();     // connect to the subscription service    var workflowSubscriptionService = workflowServicesManager.GetWorkflowSubscriptionService();     // get all workflow associations    var workflowAssociations = workflowSubscriptionService.EnumerateSubscriptionsByDefinition(firstWorkflowDefinition.Id);     _sharepoint.Load(workflowAssociations);    _sharepoint.ExecuteQuery();     foreach (var association in workflowAssociations)    {        Console.WriteLine("{0} - {1}",        association.Id, association.Name);    }     return true; }
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String queryFields = null;              for(Schema.FieldSetMember field : SObjectType.Task.FieldSets.Activity_Detail_Page.getFields()){                  queryFields = (queryFields == null ? field.getFieldPath() : queryFields+', '+field.getFieldPath());               }                String query = 'Select '+queryFields+' from Task where Id=\''+activityId+'\'';               task = Database.query(query);   i'll creating a field-set,now how do i add link on any field?  above code is  for dynamically query creation . below code of page   &lt;apex:pageBlock title="Activity" id="Block1"&gt;       &lt;apex:pageBlockSection title="Activity Detail"&gt;         &lt;apex:repeat value="{!$ObjectType.Task.FieldSets.Activity_Detail_Page}" var="field"&gt;             &lt;apex:outputField value="{!Task[field.fieldPath]}" /&gt;         &lt;/apex:repeat&gt;     &lt;/apex:pageBlockSection&gt; &lt;/apex:pageBlock&gt;    As per the image attached, I want to add a link in Rounded field that liks to account. Can any one help me?
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I'm new to Apex and development in general... So, I'm playing around coding and doing some badges in Trailhead. I created a small piece of code, as below, and have no actual use: public class GenderIdentifier {     public void DetermineGender(String Gender){                 if (Gender == 'Man'){             Gender = 'Male';             } else {             Gender = 'Female';         }            } }  If I make the method 'non-static' it works, and I can see it working fine executing as a anonymous block. If I make it static, I can't execute the anonymous block, as I get an Error like:  Non static method cannot be referenced from a static context: void GenderIdentifier.DetermineGender(String)  What am I doing wrong? It would make sense to have a method like this as Static. I think I misunderstood the concept of static methods.