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  • Tech Article: Tired of Null Pointer Exceptions? Use Java SE 8's Optional!

    - by Tori Wieldt
    A wise man once said you are not a real Java programmer until you've dealt with a null pointer exception. The null reference is the source of many problems because it is often used to denote the absence of a value. Java SE 8 introduces a new class called java.util.Optional that can alleviate some of these problems. In the tech article "Tired of Null Pointer Exceptions? Use Java SE 8's Optional!" Java expert Raoul-Gabriel Urma shows you how to make your code more readable and protect it against null pointer exceptions. Urma explains "The purpose of Optional is not to replace every single null reference in your codebase but rather to help design better APIs in which—just by reading the signature of a method—users can tell whether to expect an optional value. In addition, Optional forces you to actively unwrap an Optional to deal with the absence of a value; as a result, you protect your code against unintended null pointer exceptions." Learn how to go from writing painful nested null checks to writing declarative code that is composable, readable, and better protected from null pointer exceptions. Read "Tired of Null Pointer Exceptions? Use Java SE 8's Optional!"

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  • Putting coworkers as references in CV [closed]

    - by Jaded
    My friend is working in one organisation for some time and wants to change a job. Problem is that motivation is money related (management is refusing to raise salary without any explanation despite 1) they don't have any questions nor problems related to his work 2) they promised raise long ago) and they won't find anyone to replace him. So they not just won't recommend him, but surely will say he is bad specialist and person as he leaves. Don't put that work in CV is not an option, so he thinks the possible solution is to reference his co-workers and teammates. He didn't work for them as employee, but he worked with them, so their (100% positive) feedback looks like fair compensation of what management will say. Is that correct? Looking for interviewers/employers opinion.

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  • MySQL Unions/Subselects not utilizing keys from associated tables

    - by Brett
    I've noticed by doing EXPLAINs that when a MySQL union between two tables is used, mysql creates a temporary table, but the temp table does not use keys, so queries are slowed considerably. Here is an example: SELECT * FROM ( SELECT `part_number`, `part_manufacturer_clean`, `part_number_clean`, `part_heci`, `part_manufacturer`, `part_description` FROM `new_products` AS `a` UNION SELECT `part` as `part_number`, `manulower` as `part_manufacturer_clean`, `partdeluxe` as `part_number_clean`, `heci` as `part_heci`, `manu` as `part_manufacturer`, `description` as `part_description` FROM `warehouse` AS `b` ) AS `c` WHERE `part_manufacturer_clean` = 'adc' EXPLAIN yields this: id select_type table type possible_keys key key_len ref rows Extra 1 PRIMARY <derived2> ALL (NULL) (NULL) (NULL) (NULL) 17206 Using where 2 DERIVED a ALL (NULL) (NULL) (NULL) (NULL) 17743 3 UNION b ALL (NULL) (NULL) (NULL) (NULL) 5757 (NULL) UNION RESULT <union2,3> ALL (NULL) (NULL) (NULL) (NULL) (NULL) In this case, part_manufacturer_clean and manulower are keys in both tables. When I don't use the subselects and union, and just use one table, everything works fine. I'm not sure if the issue is with the union or with the subselects. Is there any way to union two tables and still use keys/indexes for performance?

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  • Distributing a very simple application

    - by vanna
    I have a very simple working console application written in C++ linked with a light static library. It is just for testing purposes. Now that the coding part is done, I would like to know the process of actually distributing the program. I wrote a very basic CMakeLists.txt that create makefiles or VS projects to build the sources. I also have a program that calls the static library in order to make some google tests. To me, the distribution of this application goes like this : to developpers : the src directory with the CMakeLists.txt file (multi-platform distribution) with a README.txt and an INSTALL.txt to users : the executable and a README.txt on my git repo : everything mentionned above plus the sources for testing and the gtest external lib A this point : considering the complexity of my application, am I doing it right ? Is there any reference that would formalize this distribution process so I can get better and go further ? Say I would like to add dynamic libraries that can be updated, external libraries like boost : how should I package this to distribute it in a professionnal way ?

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  • Best method in PHP for the Error Handling ? Convert all PHP errors (warnings notices etc) to exceptions?

    - by user1179459
    What is the best method in PHP for the Error Handling ? is there a way in PHP to Convert all PHP errors (warnings notices etc) to exceptions ? what the best way/practise to error handling ? again: if we overuse exceptions (i.e. try/catch) in many situations, i think application will be halted unnecessary. for a simple error checking we can use return false; but it may be cluttering the coding with many if else conditions. what do you guys suggest ?

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  • HRESULT E_FAIL Exception! (5 replies)

    Hi, I am trying to generate a powerpoint presentation in C#. It works well on my local machine which is running XP. When I run the application on Windows Server 2003 (our Server) the presentation gives HRESULT E FAIL when I call the following code chart (Microsoft.Office.Interop.Graph.Chart)slide.Shapes.AddOLEObject (GetLeft(i), GetTop(i), GetWidth(i), GetHeight(i), &quot;MSGraph.Chart&quot;, &quot;&quot;, Microsoft....

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  • The Connection String Reference Site

    - by Yousef_Jadallah
    In this great site http://www.connectionstrings.com/ you can find about 517 connection strings and 120 providers, drivers and class libraries listed in the database. These for Database Servers as well Data Files. Just you need to choose the needed element then you will get all the information that you calling for.   Hope this helps,

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  • What's the reason in your mind Exception are heavily used in Managed (C# and Java) language but not in C++?

    - by ZijingWu
    AFAIK, a lot of C++ projects don't allow exceptions and deny them in coding guidelines. I have a lot of reasons, for example, Exception is hard to handle correctly if your binary needs to be compiled by separate and different compilers. But it doesn't fully convince me, there is a lot of projects which are just using one compiler. Compared to C++, Exceptions are heavily used in C# and Java and the reason can only be that Exception are not bringing enough benefit. One point is Debugbility in practice. Exception can not get the call stack in C++ code, but in C# and Java you can get the call stack from Exception, it is significant and makes debugging easier. No-CallStack is not the fault of the Exception, it is the language difference , but it impacts the Exception usage. So what's the reason that exceptions are frowned upon in c++ programs?

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  • Software development based on a reference implementation

    - by Kanishka Dilshan
    Lets say I have library "A2" as a dependency in a project. Library "A2" is derived from library "A1" where someone has done few changes to the library "A1" 's source code. Lets say there is a new version of "A1" I want to use the new version but no modification to its sourcecode at all. I am planning to identify what are the changes done to the original library when deriving library "A2" out of it and decorate the latest version of the library with those changes. Is it a good approach to solve this? if not can someone suggest the best approach to solve this kind of problems?

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  • How add service reference in visual studio 2008 authenticating against password-protected web servic

    - by user312305
    Hello, first time here... great site Well, I want to reference a web service, and it requires user/pass authentication. In VS 2008, if I try to "add reference", or "add service reference", all I can type is the URL, there's no way to input my credentials. Obviously, if I try to load the ws, it shows me a nice message: "The request failed with HTTP status 403: Forbidden. Metadata contains a reference that cannot be resolved: The HTTP request is unauthorized with client authentication scheme 'Anonymous'. The authentication header received from the server was 'Basic realm="weblogic"'. The remote server returned an error: (401) Unauthorized." So my question is: Is it possible (using VS 2008) to add a reference to a web service that is protected? How? Any help is kindly appreciated. Thanks!

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  • Foreign key reference to a two-column primary key

    - by Adam Ernst
    One of my tables has a two-column primary key: CREATE TABLE tournament ( state CHAR(2) NOT NULL, year INT NOT NULL, etc..., PRIMARY KEY(state, year) ); I want a reference to the tournament table from another table, but I want this reference to be nullable. Here's how I might do it, imagining that a winner doesn't necessarily have a tournament: CREATE TABLE winner ( name VARCHAR NOT NULL, state CHAR(2) NULL, year INT NULL ); If state is null but year is not, or vice-versa, the table would be inconsistent. I believe the following FOREIGN KEY constraint fixes it: ALTER TABLE winner ADD CONSTRAINT FOREIGN KEY fk (name, state) REFERENCES tournament (name, state); Is this the proper way of enforcing consistency? Is this schema properly normalized?

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  • No_data_found exception is progating in outer block also?

    - by Vineet
    In my code i am entering the salary which is not available in employees table and then again inserting duplicate employee_id in primary key column of employee table in exception block where i am handling no data found exception but i do not why 'No data found exception in the end also? OUTPUT coming: Enter some other sal ORA-01400: cannot insert NULL into ("SCOTT"."EMPLOYEES"."LAST_NAME") ORA-01403: no data found --This should not come according to logic This is the code DECLARE v_sal number:=&p_sal; v_num number; BEGIN BEGIN select salary INTO v_num from employees where salary=v_sal; EXCEPTION WHEN no_data_found THEN DBMS_OUTPUT.PUT_LINE('Enter some other sal'); INSERT INTO employees (employee_id)values(100) ; END; EXCEPTION WHEN OTHERS THEN DBMS_OUTPUT.PUT_LINE(sqlerrm); END;

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  • in C# try -catch , can't catch the exception

    - by sunglim
    below code can't catch the exception. does catch can't catch the exception which occured in the function? try { Arche.Members.Feedback.FeedbackBiz_Tx a = new Arche.Members.Feedback.FeedbackBiz_Tx(); a.AddFreeSubscriptionMember(itemNo, buyerID, itemName, DateTime.Today, DateTime.Today); } catch(Exception ex) { RegisterAlertScript(ex.Message); } ... public void AddFreeSubscriptionMember(string itemNo, string buyerID, string itemName, DateTime fsStartDate, DateTime fsEndDate) { FeedbackBiz_NTx bizNTx = new FeedbackBiz_NTx(); if (bizNTx.ExistFreeSubscription(buyerID, itemNo)) { throw new Exception("Exception."); }

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  • How to deserialize null array to null in c#?

    - by Aen Sidhe
    Here is my class: public class Command { [XmlArray(IsNullable = true)] public List<Parameter> To { get; set; } } When I serialize an object of this class: var s = new XmlSerializer(typeof(Command)); s.Serialize(Console.Out, new Command()); it prints as expected (xml header and default MS namespaces are omitted): <Command><To xsi:nil="true" /></Command> When I took this xml and tried to deserialize it I got stucked, because it always print "Not null": var t = s.Deserialize(...); if (t.To == null) Console.WriteLine("Null"); else Console.WriteLine("Not null"); How to force deserializer to make my list null, if it is null in xml?

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  • Add Web Reference prompts for credentials with "Discovery Credential" dialog but won't accept valid

    - by Eden
    I'm attempting to add a web reference to my ASP.Net 3.0 project. This is a reference to the SQL Server Reporting Services web service. I have verified the service is up and running, but when I try to add the web reference in my project, I am prompted for my credentials, which I enter, and then prompted again and again and again. I have to hit cancel to stop the vicious cycle. When I do that the service definition comes up in the window, but the "Add Reference" button is disabled so I can't add the reference to my project. I have limited knowledge of SQL Reporting Services configurations. If anyone knows how to resolve this problem I'd really appreicate it.

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  • Efficiency of checking for null varbinary(max) column ?

    - by Moe Sisko
    Using SQL Server 2008. Example table : CREATE table dbo.blobtest (id int primary key not null, name nvarchar(200) not null, data varbinary(max) null) Example query : select id, name, cast((case when data is null then 0 else 1 end) as bit) as DataExists from dbo.blobtest Now, the query needs to return a "DataExists" column, that returns 0 if the blob is null, else 1. This all works fine, but I'm wondering how efficient it is. i.e. does SQL server need to read in the whole blob to its memory, or is there some optimization so that it just does enough reads to figure out if the blob is null or not ? (FWIW, the sp_tableoption "large value types out of row" option is set to OFF for this example).

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  • Liqn to sql null-able value in query

    - by msony
    I need get all items what have no categories int? categoryId = null; var items=db.Items.Where(x=>x.CategoryId==categoryId); this code generate in where: where CategoryId=null instead of where CategoryId is null ok, when i write var items=db.Items.Where(x=>x.CategoryId==null); in my sql profiler it works: where CategoryId is null BUT when i do this HACK it doesn't: var items=db.Items.Where(x=>x.CategoryId==(categoryId.HasValue ? categoryId : null)); so what's the problem? is there by in L2S?

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  • php 5.3.2 not throwing exceptions

    - by tipu
    I'm attempting to throw an exception using php 5.3.2 and it is giving me the following error: Parse error: syntax error, unexpected T_THROW I am attempting to throw an exception the following way: throw new Exception('Property ' . $name . ' doesn\'t exist in class Index', ''); Edit: I also tried throw new Exception('Property ' . $name . ' doesn\'t exist in class Index'); it didn't change the error I was getting. The complete method: public function __get($name) { if(property_exists($this, $name) throw new Exception('Property ' . $name . ' doesn\'t exist in class Index'); return $this->$name; }

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  • getting detailed information about structured exceptions

    - by Martin
    My Visual C++ application is compiled with /EHA option, letting me catch structured exceptions (division by zero, access violation, etc). I then translate those exceptions to my own exception class using _set_se_translator(). My goal is to improve our logging of those types of exceptions. I can get the type of exception from the EXCEPTION_RECORD structure, and the exception address. I would like to be able to gather more information, like the source file/location where the exception is thrown, the call stack, etc. Is that possible? I do create an exception minidump on structured exceptions - is there a tool to automatically get the call stack from that?

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