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  • Persist data when the table was not mapped (JPA EclipseLink)

    - by enrique
    Hi everybody I need some help in persisting data into a table that has not been mapped... The issue is that the database we have has a table which all of its columns are foreign keys so by mapping the whole database all of the tables are correctly mapped. However that table called "category" is not mapped. The way in which we can browse the data is by passing for the table I mentioned using the @jointable annotation which was set by the system in the other tables with which "category" has a relation. So we can go ahead and using the collections and perform a query. But the issue comes when I want to persist data into that table because there´s no any entity. We tried to persist through the collections but no luck. Then I have just tried by creating the entity with its PK and Facade all by hand. However when I try to persist using the Merge method the system tries to perform an Insert when it is supposed to perform an Update. So obviously it returns an error. Does anybody have an idea on this situation? Thanks.-

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  • Accessing variablss through a different class within the constructor of latter classes of an object

    - by Haxed
    In the code below, I've added two lines that print output. The first line prints junk as usual, but surprisingly the second one gives me a compilation error. Why? class Student { private String name; public Student(String name){ this.name = name; } public String getName(){ return name; } } class StudentServer { public StudentServer(){ Student[] s = new Student[30]; s[0] = new Student("Nick"); // LINE 01: This compiles, although prints junk System.out.println(s[0]); // LINE 02: I get a error called cannot find symbol System.out.println(s[0].getName()); } public static void main(){ new StudentServer(); } } Many Thanks

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  • How can find out the system default currency symbol on BlackBerry?

    - by ageektrapped
    I have a need to display a currency value in my application. There doesn't seem to be an easy way to do this with the RIM API, so I'm reduced to creating my own solution (a common refrain for BlackBerry development, unfortunately) Currently I'm using the Formatter class, from javax.microedition.locale like so protected String formatResult(double result) { try { Locale l = Locale.getDefaultForSystem(); Formatter formatter = new Formatter(l.toString()); return formatter.formatCurrency(result); } catch (UnsupportedLocaleException e) { return "This fails for the default locale because BlackBerry sucks"; } } I always hit the catch block in the simulator. Since this doesn't work by default on the simulator, I'm hesitant to put it in the application. So I have two questions: Can anyone tell me if the above solution is the way to go? And how to fix it, of course. Is there a way I can retrieve the currency symbol for the current locale programmatically so I can format myself?

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  • Does Socket open another thread? Does it return something?

    - by Roman
    In the client application I call new Socket(serverIP,serverPort). As a result the client application sends a request to the server application to open a socket. Does it start a new thread? I mean which of the following is true? Client application sends a request and immediately starts to execute following commands (not weighting for the answer). Client sends the request and weights for the answer. As soon as the answer is obtained, the client application continues to execute following commands. The second case seems to be more realistic and logical for me. However, I do not understand what happens if the server does not open a socket and it does not say that it does not "want" to open the second (it can happen if the server does not exist or network is broken). What will happen in this case? Will server weight forever? In general it would be nice for the client to know what is the result of its request for the socket. For example I can imagine the following situations: The socket is opened by the server. The server refuses to open a socket. So, server exists, it got the request from the client but it says "no". There is no response from the server. I know that new Socket(serverIP,serverPort) does not "return" this kind of information. But it throws exceptions. One of them is "UnkownHostException". When it is thrown? When the server is not responding for a while (for how long)? ADDED: I just found out that UnknownHostException is thrown to indicate that the IP address of a host could not be determined. So, it is unrelated with the above described situations (server is not responding, server refuses to open a socket).

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  • How to find out efficiently the auto-generated id for a new object when using JPA?

    - by webstarg
    Hello, I have an attribute which is annotated with @Id. The ID is going to be generated automatically when persisting the object. That means that the ID-value is not defined before I persist the object. After persisting it, it has an ID (in the database), but unfortunately the field still remains null as long as I don't reload it from the DB. is there any easy way to find out the generated id? Or better: To configure that it will be written into the field? Thanks in advance

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  • Why does Eclipse crash with Xmx, XX:MaxPermSize above certain values?

    - by alex
    Running Eclipse 3.5.1, JDK 1.6.0_17 on WinXP SP3 32Bit with 3.5 gigs of RAM. I'm aware of the known Eclipse best practices, still trying to figure out eclipse.ini. This will launch: -Xmx588m and this won't: -Xmx589m. Same with -XX:MaxPermSize. Anything above -XX:MaxPermSize=140m won't launch. The screen of death is simlar to this (taken from here). Any ideas on why might this be happening?

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  • Configure multiple keystores in JBoss depending on requested hostname

    - by Mo
    Hello, I have my J2EE application deployed into a JBossAS. My Application has to respond to two different hostnames (https://foo.com/myApp and https://bar.com/myApp). It is the same instance of the app serving those two hostnames. But I don't know how to configure the keystores. I need different keystores for each hostname. Is there a way to tie a virtual host in JBoss' server.xml to a specific connector? Or do I have to use two different IP-addresses and create a connector for each? A solution that does not require a second IP-address would be greatly appreciated.

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  • JNI - native method with ByteBuffer parameter

    - by Ajan
    I've got a method: public native void doSomething(ByteBuffer in, ByteBuffer out); Generated by javah C/C++ header of this method is: JNIEXPORT void JNICALL Java__MyClass_doSomething (JNIEnv *, jobject, jobject, jobject, jint, jint); How can I get a data array from jobject (that is a ByteBuffer instance) ?

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  • What's the reason behind the jumping GeneratedValue(strategy=GenerationType.TABLE) when not specifyi

    - by joeduardo
    Why do I need to add allocationSize=1 when using the @TableGenerator to ensure that the id wouldn't jump from 1, 2,... to 32,xxx, 65,xxx,... after a jvm restart? Is there a design reason for the need to specify the allocationSize? This snippet would produce the jumping ids @Id @GeneratedValue(strategy = GenerationType.TABLE) private Long id; Here's the modified snippet that produces the properly sequenced ids @Id @GeneratedValue(strategy = GenerationType.TABLE, generator = "account_generator") @TableGenerator(name = "account_generator", initialValue = 1, allocationSize = 1) private Long id;

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  • one more time about loop that doesn't work

    - by unit
    I have asked a couple of questions about this for loop: String[] book = new String [ISBN_NUM]; bookNum.replaceAll("-",""); if (bookNum.length()!=ISBN_NUM) throw new ISBNException ("ISBN "+ bookNum + " must be 10 characters"); for (int i=0;i<bookNum.length();i++) { if (Character.isDigit(bookNum.charAt(i))) book[j]=bookNum.charAt(i); //this is the problem right here j++; if (book[9].isNotDigit()|| book[9]!="x" || book[9]!="X") throw new ISBNException ("ISBN " + bookNum + " must contain all digits" + "or 'X' in the last position"); } which will not compile. An answer I had from the other question I asked told me that the line where the error occurs is wrong in that bookNum.charAt(i) is an (immutable) string, and I can't get the values into a book array that way. What I need to do on my assignment is check an ISBN number (bookNum) to see that it is all numbers, except the last digit can be an 'x' (valid ISBN). Is this the best way to do it? If so, what the hell am I doing wrong? If not, what method would be a better one to use?

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  • Hibernate Many-To-One Foreign Key Default 0

    - by user573648
    I have a table where the the parent object has an optional many-to-one relationship. The problem is that the table is setup to default the fkey column to 0. When selecting, using fetch="join", etc-- the default of 0 on the fkey is being used to try over and over to select from another table for the ID 0. Of course this doesn't exist, but how can I tell Hibernate to treat a value of 0 to be the same as NULL-- to not cycle through 20+ times in fetching a relationship which doesn't exist? <many-to-one name="device" lazy="false" class="Device" not-null="true" access="field" cascade="none" not-found="ignore"> <column name="DEVICEID" default="0" not-null="false"/>

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  • Design issue when having classes implement different interfaces to restrict client actions

    - by devoured elysium
    Let's say I'm defining a game class that implements two different views: interface IPlayerView { void play(); } interface IDealerView { void deal(); } The view that a game sees when playing the game, and a view that the dealer sees when dealing the game (this is, a player can't make dealer actions and a dealer can't make player actions). The game definition is as following: class Game : IPlayerView, IDealerView { void play() { ... } void deal() { ... } } Now assume I want to make it possible for the players to play the game, but not to deal it. My original idea was that instead of having public Game GetGame() { ... } I'd have something like public IPlayerView GetGame() { ... } But after some tests I realized that if I later try this code, it works: IDealerView dealerView = (IDealerView)GameClass.GetGame(); this works as lets the user act as the dealer. Am I worrying to much? How do you usually deal with this patterns? I could instead make two different classes, maybe a "main" class, the dealer class, that would act as factory of player classes. That way I could control exactly what I would like to pass on the the public. On the other hand, that turns everything a bit more complex than with this original design. Thanks

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  • Why does this compile?

    - by akf
    I was taken aback earlier today when debugging some code to find that something like the following does not throw a compile-time exception: public Test () { HashMap map = (HashMap) getList(); } private List getList(){ return new ArrayList(); } As you can imagine, a ClassCastException is thrown at runtime, but can someone explain why the casting of a List to a HashMap is considered legal at compile time?

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  • So I dynamically load a jar at runtime how do I use it?

    - by justinhj
    So question 194698 shows how to load a jar file at runtime and you can load individual named classes and get a Class object. Now my problem is I want to be able to cast those Classes to the types they really are, but I can't because I can't use an import since the whole point is to load it at runtime rather than compile time. It seems like the way to go is to use reflection to discover the functions and field names, but that seems brittle since the API in the jar files could change and the code won't break until it is run. Is there a better way?

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  • hibernate restrictions.in with and, how to use?

    - by cometta
    I have table like below id, employee_no, survey_no, name 1 test 1 test_name 2 test2 1 test_name2 3 test3 1 test_name3 4 test4 2 test_name4 how to query with Restriction.in by combining below AND into one IN statement? IN[ (if(survey_no==1) && employee_no== 'test') , (if(survey_no==1) && employee_no== 'test2') , ... ]

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  • How do i detect the deprecated methods in a program?

    - by manus91
    I've searched through the web and what I've found out is this: To make the compiler warn you of the details of which methods you used that were deprecated use the javac.exe -deprecation switch. Then look in the Javadoc for the deprecated methods to find out the recommended replacements. Sometimes you just have to rename. Sometimes the replacements work quite differently. But I'm not really understand how it works, can anybody help me with this?

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  • How can I configure a Hudson job to use a specific JDK?

    - by rewbs
    I have a number of projects running on a Hudson slave. I'd like one of them to run Ant under Java6, rather than the default (which is Java5 in my environment). In the project configuration view, I was hoping to find either: An explicit option allowing me to set a custom JDK location to use for this project. A way to set custom environment variables for this project, which would allow me to set JAVA_HOME to the JDK6 location. The would make Ant pick up and run on Java6 as desired. Is there a way to do either of the above? If one of those facilities is available, I can't see how to access it. I'm running on Hudson 1.285. I would rather avoid using an "execute shell" operation instead of the "invoke Ant" operation if possible: my slave is on z/OS and Hudson doesn't seem to create the temporary shell scripts properly on this platform (probably an encoding issue).

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