Search Results

Search found 21111 results on 845 pages for 'null pointer'.

Page 483/845 | < Previous Page | 479 480 481 482 483 484 485 486 487 488 489 490  | Next Page >

  • How does polymorph ambiguity distinction work?

    - by Pentius
    Given I have a class with two constructors: public class TestClass { ObjectOne o1; ObjectTwo o2; public TestClass(ObjectOne o1) { // .. } public TestClass(ObjectTwo o2) { // .. } } What happens, if I call: new TestClass(null); How to determine the correct method to call? And who determines that? Are there differences between Java and other OOP languages?

    Read the article

  • Request URL in Javascript, Fetch URL Content using Java Applet, return to Javascript?

    - by Sam G
    I'm in the process of making a little experiment, it grabs a YouTube page, and returns the highest quality MP4 link, then plays this in a HTML 5 Video element. Now I was using PHP with cURL to get the URL content (YouTube), but that only works on my local server (MP4 link is locked to IP address). I can't think of any other way to get the page content due to cross domain rules except a Java applet. So I've built a Java applet that should return the content of a URL. Java import java.applet.Applet; import java.awt.*; import java.io.ByteArrayOutputStream; import java.io.InputStream; import java.net.HttpURLConnection; import java.net.URL; public class URLFetcherabc extends Applet { public void init() { } public void paint(Graphics g) { g.drawString("Java loaded. Waiting for URL", 0, 10); } public String getURL(String url, String httpMethod) { try { URL u = new URL(url); HttpURLConnection conn = (HttpURLConnection)u.openConnection(); conn.setRequestMethod(httpMethod); InputStream is = conn.getInputStream(); ByteArrayOutputStream output = new ByteArrayOutputStream(); byte[] buffer = new byte[1024]; for (int bytesRead = 0; (bytesRead = is.read(buffer)) != -1; ) { output.write(buffer, 0, bytesRead); } return output.toString(); } catch (Exception e) { }return null; } } Now I've got the applet on the page, but every-time I call the function it returns nothing. Heres my HTML for including the applet. HTML <applet id="URLFetcher" name="URLFetcher" code="URLFetcherabc.class" archive="URLFetcher.jar" height="200" width="200" mayscript=""></applet> Java-Script function fetchurl(urltofetch) { var URLFetcher = document.getElementById("URLFetcher"); var result = URLFetcher.getURL(urltofetch); //Result = URL Content return result; } The function always returns null, in Java the function does work when passed a variable via other means (parameter etc). I've tried running other functions through Javascript and the Java applet does respond. I'm new to Java applets and communicating with them via Javascript, so I'm probably making either a small mistake somewhere or its completely wrong. Any ideas? Thanks

    Read the article

  • Different behavior of reflected generic delegates with and without debugger

    - by Andrew_B
    Hello. We have encountered some strange things while calling reflected generic delegates. In some cases with attatched debuger we can make impossible call, while without debugger we cannot catch any exception and application fastfails. Here is the code: using System; using System.Windows.Forms; using System.Reflection; namespace GenericDelegate { public partial class Form1 : Form { public Form1() { InitializeComponent(); } private delegate Class2 Delegate1(); private void button1_Click(object sender, EventArgs e) { MethodInfo mi = typeof (Class1<>).GetMethod("GetClass", BindingFlags.NonPublic | BindingFlags.Static); if (mi != null) { Delegate1 del = (Delegate1) Delegate.CreateDelegate(typeof (Delegate1), mi); MessageBox.Show("1"); try { del(); } catch (Exception) { MessageBox.Show("No, I can`t catch it"); } MessageBox.Show("2"); mi.Invoke(null, new object[] {});//It's Ok, we'll get exception here MessageBox.Show("3"); } } class Class2 { } class Class1<T> : Class2 { internal static Class2 GetClass() { Type type = typeof(T); MessageBox.Show("Type name " + type.FullName +" Type: " + type + " Assembly " + type.Assembly); return new Class1<T>(); } } } } There are two problems: Behavior differs with debugger and without You cannot catch this error without debugger by clr tricks. It's just not the clr exception. There are memory acces vialation, reading zero pointer inside of internal code. Use case: You develop something like plugins system for your app. You read external assembly, find suitable method in some type, and execute it. And we just forgot about that we need to check up is the type generic or not. Under VS (and .net from 2.0 to 4.0) everything works fine. Called function does not uses static context of generic type and type parameters. But without VS application fails with no sound. We even cannot identify call stack attaching debuger. Tested with .net 4.0 The question is why VS catches but runtime do not?

    Read the article

  • Unable to find assembly, C#

    - by PlasmaCube
    So, here's the deal. I've got two ASP.NET applications, both of which use SQLServer Session State management. They also both use the same server. I've got a custom session class in an external DLL, which fully implements serialization, and which both applications have referenced. Each application, in turn, has a class which inherits from the DLL class, and both applications use their own respective classes for their session state. Now, what I was trying to accomplish was that if you wanted to go to the other application, it could look in the session (they all use the same session key) and treat the existing object there as the base (the one from the DLL), extract whatever login info you need, then overwrite the session object with your own. Unfortunately, when the second application attempts to read the session, it seems that it looks for the DLL of the first application, and when it can't find it, it throws an exception. Is there a flaw in my logic? Here's an example: // Global.asax of the 1st app protected void Session_Start(object sender, EventArgs e) { Session.Add( "UserSessionKey", new FirstUserSession()); // FirstUserSession inherits from BaseUserSession } Now the second application: // Global.asax of 2nd app protected void Session_Start(object sender, EventArgs e) { if (Session["UserSessionKey"] != null) { BaseUserSession existing = (BaseUserSession)Session["UserSessionKey"]; SecondUserSession session = new SecondUserSession(); // This also inherits from BaseUserSession session.Authenticated = existing.Authenticated; session.Id = existing.Id; session.Role = existing.Role; Session.Add("UserSessionKey", session); } else { Session.Add("UserSessionKey", new SecondUserSession()); } } Here's the exception stack trace. In this case, "MyCBC" is the real name of the first app, and "ASPTesting" is the second app. [SerializationException: Unable to find assembly 'MyCBC, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null'.] System.Runtime.Serialization.Formatters.Binary.BinaryAssemblyInfo.GetAssembly() +1871092 System.Runtime.Serialization.Formatters.Binary.ObjectReader.GetType(BinaryAssemblyInfo assemblyInfo, String name) +7545734 System.Runtime.Serialization.Formatters.Binary.ObjectMap..ctor(String objectName, String[] memberNames, BinaryTypeEnum[] binaryTypeEnumA, Object[] typeInformationA, Int32[] memberAssemIds, ObjectReader objectReader, Int32 objectId, BinaryAssemblyInfo assemblyInfo, SizedArray assemIdToAssemblyTable) +120 System.Runtime.Serialization.Formatters.Binary.ObjectMap.Create(String name, String[] memberNames, BinaryTypeEnum[] binaryTypeEnumA, Object[] typeInformationA, Int32[] memberAssemIds, ObjectReader objectReader, Int32 objectId, BinaryAssemblyInfo assemblyInfo, SizedArray assemIdToAssemblyTable) +52 System.Runtime.Serialization.Formatters.Binary.__BinaryParser.ReadObjectWithMapTyped(BinaryObjectWithMapTyped record) +190 System.Runtime.Serialization.Formatters.Binary.__BinaryParser.ReadObjectWithMapTyped(BinaryHeaderEnum binaryHeaderEnum) +61 System.Runtime.Serialization.Formatters.Binary.__BinaryParser.Run() +253 System.Runtime.Serialization.Formatters.Binary.ObjectReader.Deserialize(HeaderHandler handler, __BinaryParser serParser, Boolean fCheck, Boolean isCrossAppDomain, IMethodCallMessage methodCallMessage) +168 System.Runtime.Serialization.Formatters.Binary.BinaryFormatter.Deserialize(Stream serializationStream, HeaderHandler handler, Boolean fCheck, Boolean isCrossAppDomain, IMethodCallMessage methodCallMessage) +203 System.Web.Util.AltSerialization.ReadValueFromStream(BinaryReader reader) +788 System.Web.SessionState.SessionStateItemCollection.ReadValueFromStreamWithAssert() +55 System.Web.SessionState.SessionStateItemCollection.DeserializeItem(String name, Boolean check) +281 System.Web.SessionState.SessionStateItemCollection.get_Item(String name) +19 System.Web.SessionState.HttpSessionStateContainer.get_Item(String name) +13 System.Web.SessionState.HttpSessionState.get_Item(String name) +13 ASPTesting._Default.Page_Load(Object sender, EventArgs e) in C:\Documents and Settings\sarsstu\My Documents\Projects\Testing\ASPTesting\ASPTesting\Default.aspx.cs:20 System.Web.Util.CalliHelper.EventArgFunctionCaller(IntPtr fp, Object o, Object t, EventArgs e) +14 System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e) +35 System.Web.UI.Control.OnLoad(EventArgs e) +99 System.Web.UI.Control.LoadRecursive() +50 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +627 Thanks to everyone in advance.

    Read the article

  • print TCHAR[] on console

    - by hara
    Hi I'm quite sure that it is a stupid issue but it drives me crazy.. how could i print on the console a TCHAR array? DWORD error = WSAGetLastError(); TCHAR errmsg[512]; int ret = FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM, 0, error, 0, errmsg, 511, NULL); i need to print errmsg...

    Read the article

  • What is root reference ?

    - by DotNetGuy
    class GCTest { static Object r1; static void Main() { r1 = new Object(); Object r2 = new Object(); Object r3 = new Object(); System.GC.Collect(); // what can be reclaimed here ? r1 = null; r3.ToString(); System.GC.Collect(); // what can be reclaimed here ? } } // code from - DonBox's Essential .Net

    Read the article

  • Created C header file, getting errors..

    - by Daniel
    Hi, I'v created a C header file (It's compiled), now when i compile my program it comes up with tons of errors like: warning: null character(s) ignored error: stray ‘\23’ in program TheFunctions.h:1722: error: stray ‘\200’ in program Inside the header file is simply two functions, which work in the normal c program. Please help!

    Read the article

  • python: equivalent to Javascript "||" to override non-truthful value

    - by Jason S
    In Javascript I can do this: function A(x) { return x || 3; } This returns 3 if x is a "non-truthful" value like 0, null, false, and it returns x otherwise. This is useful for empty arguments, e.g. I can do A() and it will evaluate as 3. Does Python have an equivalent? I guess I could make one out of the ternary operator a if b else c but was wondering what people use for this.

    Read the article

  • change a frame's attribute by pressing a button

    - by asavu
    Hi. Suppose we have a JFrame named frame1 with a String attribute named credentials set inittially to null. I have a jButton named button1 attached to the frame and I want to change the frame1 String credentials attribute by pressing button1. I need some piece of advice regarding the ActionListener code especially. Could you guys pls help me? Thank you.

    Read the article

  • Problem using generics in function

    - by JAVA
    Hi all, I have this functions and need to make it one function. The only difference is type of input variable sourceColumnValue. This variable can be String or Integer but the return value of function must be always Integer. I know I need to use Generics but can't do it. public Integer selectReturnInt(String tableName, String sourceColumnName, String sourceColumnValue, String targetColumnName) { Integer returned = null; String query = "SELECT "+targetColumnName+" FROM "+tableName+" WHERE "+sourceColumnName+"='"+sourceColumnValue+"' LIMIT 1"; try { Connection connection = ConnectionManager.getInstance().open(); java.sql.Statement statement = connection.createStatement(); statement.execute(query.toString()); ResultSet rs = statement.getResultSet(); while(rs.next()){ returned = rs.getInt(targetColumnName); } rs.close(); statement.close(); ConnectionManager.getInstance().close(connection); } catch (SQLException e) { System.out.println("???????? ?? ???? ?? ???? ?????????!"); System.out.println(e); } return returned; } // SELECT (RETURN INTEGER) public Integer selectIntReturnInt(String tableName, String sourceColumnName, Integer sourceColumnValue, String targetColumnName) { Integer returned = null; String query = "SELECT "+targetColumnName+" FROM "+tableName+" WHERE "+sourceColumnName+"='"+sourceColumnValue+"' LIMIT 1"; try { Connection connection = ConnectionManager.getInstance().open(); java.sql.Statement statement = connection.createStatement(); statement.execute(query.toString()); ResultSet rs = statement.getResultSet(); while(rs.next()){ returned = rs.getInt(targetColumnName); } rs.close(); statement.close(); ConnectionManager.getInstance().close(connection); } catch (SQLException e) { System.out.println("???????? ?? ???? ?? ???? ?????????!"); System.out.println(e); } return returned; }

    Read the article

  • Use the style defined in resource dictionary :

    - by Malcolm
    I have a style defined for listboxitem in a resource dictionary. I want to use this style in a cs file of listbox : I am doing the below thing but it gives me null ,CustomListBoxItemStyle is a name of a key given to the style. public class CustomListBox : ListBox { public CustomListBox() { this.ItemContainerStyle = Application.Current.Resources["CustomListBoxItemStyle"] as Style; } } There is no xaml for this. How to achieve this?

    Read the article

  • Does table (string, string) require index?

    - by abatishchev
    In my database running on SQL Server 2008 R2 I have a special table for global variables: CREATE TABLE global_variables ( name NVARCHAR(50), value NVARCHAR(50) NOT NULL CONSTRAINT PK_global_variables PRIMARY KEY CLUSTERED ( name ASC ) WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] ) ON [PRIMARY] GO Does such table require indexing on value or not?

    Read the article

  • JDBC Code Change From SQL Server to Oracle

    - by BeginnerAmongBeginners
    In the JDBC code, I have the following that is working with SQL Server: CallableStatement stmt = connection.prepareCall("{ call getName() }"); ResultSet rs = stmt.executeQuery(); if(rs != null) { while(rs.next()) { //do something with rs.getString("name") } } Multiple rows are returned for the above situation. I understand that the use of a cursor is required to loop through the table in Oracle, but is there any way to keep the above code the same and accomplish the same thing? Thanks in advance.

    Read the article

  • How to enforce a 5-minute per post rule in a session object in Java?

    - by John
    I'm trying to figure out how to enforce a 5 minute per post/action rule. I'm developing a web application with Wicket in Java and I've got a session class which I was planning on using to keep track of these timers on a per-user basis. I wasn't planning on storing the timestamp in a database. public boolean isAllowedToPost() { if(null OR has 5 minutes passed since last post) { // set the new timestamp return true; } else { return false; } }

    Read the article

  • how to display bigger resolution images in android?

    - by UMMA
    dear friends, referring to the code example of mine http://stackoverflow.com/questions/2997703/android-remote-image-getting-problem how can i accommodate bigger resolution images in android. when i try to display bigger resolution image from internet it give me null bitmap. any one guide me whats the solution? any help would be appreciated.

    Read the article

  • MYSQL trigger to select from and update the same table gives error #1241 - Operand should contain 1 column(s)

    - by Bipin
    when i try to select and update the same table mysql gives error error #1241 - Operand should contain 1 column(s) The trigger is DELIMITER $$ CREATE TRIGGER visitor_validation BEFORE INSERT ON ratingsvisitors FOR EACH ROW BEGIN SET @ifexists = (SELECT * FROM ratingcounttracks WHERE userid=New.vistorid AND likedate=New.likevalidation AND countfor=New.likeordislike); IF (@ifexists = NULL) THEN INSERT INTO ratingcounttracks(userid, likedate, clickcount,countfor) values (New.vistorid, New.likevalidation ,'1',New.likeordislike); ELSE UPDATE ratingcounttracks SET clickcount=clickcount+1 WHERE userid=New.vistorid AND likedate=New.likevalidation AND countfor=New.likeordislike; END IF; END$$

    Read the article

< Previous Page | 479 480 481 482 483 484 485 486 487 488 489 490  | Next Page >