1. What purpose does Class.forName() serve if you don't use the return value? stackoverflow.comI've seen this line in a sample application for using a commercial JDBC driver: |
2. how does Class.forName() work stackoverflow.comi just learnt about java.sql package. it uses class.forName() to dynamically load the driver which extends DriverManager. then we get connection using DriverManager.getConnection() method. so how does the entire thing work? how does DriverManager class ... |
3. JDBC Class.forName vs DriverManager.registerDriver stackoverflow.comWhich is the difference from |
4. What is the purpose 'Class.forName("MY_JDBC_DRIVER")' ? stackoverflow.comI understand that class loading is useful for load the class at runtime with its class name. However while using JDBC in our project we know which driver we are going ... |
5. Class.forname() and Access coderanch.com |
6. Class.forname coderanch.com |
7. Class.forName(....) is not working coderanch.comHi, all, I am trying to connect JDBC to MS access. To register the driver in the ODBC data souce administrator from the control panel, I selected MS access data base, then clicked Add, then selected Driver do MS access, click Finish and followed the instruction. However, I keep getting the "Exit from Class not found exception" (see the code below). ... |
9. Class.forName coderanch.com |
10. how class.forname() works? coderanch.com |
11. What is the format for Class.forName(...) coderanch.comI was concerned that the behaviour of registering the same driver twice was not documented in the API so I had a quick look at the DriverManager source code. It's available with the JDK if you want to look for yourself. registerDriver essentially adds the required Driver to a Vector, so adding it twice with the same Driver instance will only ... |
12. Use of Class.forName() coderanch.comYou should always use Class.forName and allow the driver to register itself and should never call DriverManager.registerDriver() directly. Otherwise, the driver registers itself when the class is loaded, and then gets registered again when you call the DriverManager. You can't stop this from occuring, since the initial load happens as the Class loads in a static code block. Chances are this ... |
13. Class.forName() problem!! coderanch.comHello people, I have this problem when i try to connect to the database, unfortunately at this line: Class.forName("com.mysql.jdbc.Driver"); I have this embedded in a try and catch but every time it throws an error back at me. I am convinced that it cant find the Driver but it is beyond me as to why, because I have put it in ... |
14. Class.forName Problem coderanch.comSee my previous response. Servlets should never just "print out" and dismiss execptions. This is not an error like the user typing in invalid data. This type of exception means that something is severely wrong with your program or setup and your servlet should let the exception propogate outward so that it blows up spectacularly in your face. By dismissing the ... |
15. Class.forName() coderanch.com |
16. Without using Class.forName... coderanch.comOriginally posted by vinod sharma: DriverManager.registerDriver( new oracle.jdbc.driver.OracleDriver()); This is not recommended, it can result in the Driver being registered twice. Once by the Driver class when the class loads in the ClassLoader, and the second time since you register it explicitly. 99.9% of the time it wont be an issue, but it means DriverManager.deregisterDriver(Driver driver) won't work, it will only ... |
17. usage of Class.forName() for loading driver coderanch.comYou're right in a way, you could directly access the Driver for your database. The design for JDBC is meant to hide specifics about the database type. In theory this allows you write code to access a database without tying yourself to a single vendor: you can change databases without rewriting a line of code. If you did it the way ... |
18. Class.forName coderanch.comNope, a static initialiser is a special block of code that will only be executed once when the Class is loaded. It is possible to load a Class several times in a single JVM and even reload a Class, but for simplicity sake assume that the block will only be run once when the class is first loaded. It looks like ... |
19. Class.forName() ? coderanch.comHi Okay here is the answer. When u say Class.forName("ABC"); Class.forName gets executed. it loads the class "ABC". In class ABC, there is a static block which gets executed as stated below public class ABC { ABC abc = null ; static { if(abc == null) { //loads and creates a new object if it does not exist ABC abc = ... |
20. Class.forName() -- doubt coderanch.com |
21. Re:Class.forName() coderanch.comA 'side effect' of this method is that it causes the Class to be loaded, but only if it has not already been loaded. The trick here is that a Driver has a 'static block' which is a section of code that gets run when the class loads. Therefore the forName() loads the Class, the static block fires, and the Driver ... |
22. what the Class.forName doing exactly. coderanch.com |
23. Internally what happens when Class.forName() is executed coderanch.comHi, 1)What you said previously about Class.forName() is exactly correct.if come to the internals Class.forName won't create any memory for your driver(note that it won't create memory for your driver only for entair object it can) at the time your instantiation.when you are trying to use that driver then only it will create memory.So that we can use memory efficiently. 2)Generally ... |
24. Class.forName(".."); coderanch.com |
25. class.forname coderanch.com |
26. Why use Class.forName() to load driver coderanch.comFirslty Thanks for replying @Anand: I agree that we can load the class with the help of the static forName() method but the string that you pass to it should still be Phonetically matching the actual class.So if this is the case then we already have the class name....just call new on it... @Stan: The Code: Driver driver = (Driver) Class.forName("COM.ibm.db2.jdbc.app.DB2Driver"). ... |
27. Class.forName() coderanch.comOriginally posted by Praveen palukuri: hi, any one can explain the exact need of Class.forName(). I know that i'll load jdbc driver if it is not loaded earlier. Other than this, is there any thing to say. Thank you. That's pretty much all there is to it. When a JDBC driver is loaded by Class.forName(), a static initialization block will cause ... |
28. What does Class.forName do? coderanch.comIt may sometimes be the case that more than one JDBC driver is capable of connecting to a given URL. For example, when connecting to a given remote database, it might be possible to use a JDBC-ODBC bridge driver, a JDBC-to-generic-network-protocol driver, or a driver supplied by the database vendor. In such cases, the order in which the drivers are tested ... |
29. Class.forName() coderanch.com |
30. What Class.forName() actually does internally? coderanch.com |
31. DriverManager.registerDriver or class.forName coderanch.com |
32. On class.forname() in JDBC coderanch.comHi All, I have below questions on class.forname() statement in JDBC connecion 1. If we do like class.forname("com.a.b.c");class.forname("com.p.q.r");... then will JVM load all classes or it will load only first one (or last one) and will ignore all others? 2. Also after using class.forname(("com.a.b.c"); we get connection as DriverManager.getConnection("jdbc:mysql:///test",user,pass) so then how exactly database url finds its corrosponding class which has ... |
33. On class.forname() in JDBC coderanch.comHi All, I have below questions on class.forname() statement in JDBC connecion 1. If we write the code like class.forname("com.a.b.c");class.forname("com.p.q.r");... then will JVM load all classes or it will load only first one (or last one) and will ignore all others? 2. Also after using class.forname(("com.a.b.c"); we get connection as DriverManager.getConnection("jdbc:mysql:///test",user,pass) so then how exactly database url finds its corrosponding class ... |
34. Class.forName coderanch.com |
35. diff b/w class.forName() & DriverManager.registerDriver coderanch.com |
36. diff b/w class.forName() & DriverManager.registerDriver coderanch.comUser code should not use the registerDriver method (look at its javadocs for an explanation) - the driver will do that by itself during its initialization, after the user code calls Class.forName. You can use several databases with different drivers without problem. Just use Class.forName for each of them, and you're good to go. |
37. Why we require Class.forName() multiple times coderanch.comThe Class.forName() registers the driver in the current JVM process and it stays registered in that process until it terminates. It does not register the driver globally on the computer for all processes to see. The registration does not have any effect outside that single process. You mention that you have two programs. I assume that means each program is running ... |
38. Class.forName() method and the new operator coderanch.comBoth can be used for creating objects at runtime. The difference is that Class.forName has the class name as a string parameter, which can be set at runtime. That means the class to be created does not have to be known at compile time (and thus does not even need to be present in the classpath). Strictly speaking, Class.forName doesn't create ... |
39. Class.forName() coderanch.comI have a DAO class getting a connection from another DAO class and it ultimately fails. The line it fails on is where it looks up Class.forName(com.microsoft.jdbc.sqlserver.SQLServerDriver). I've only figured this out by putting System.outs everywhere. There's absolutely nothing that tells me why it fails at that line. It works when I run it on my dekstop using WSAD and fails ... |
40. Use of Class.forName() in JDBC coderanch.com |
41. Class.forName() doubt coderanch.com |
42. class . forName() Vs DriverManager . registerDriver coderanch.com |
43. Class.forname() return coderanch.com |
44. Class.forName()? coderanch.com |
45. Class.forName("") coderanch.comhi , I have to get a connection and do databse operations. I know the following things. but how to make set up to avoid ClassNotFoundException. code is: try{ Class c = Class.forName("OracleDriverName"); Connection connection = DriverManager.getConnection("URL","USER","PWD"); System.out.println("helloWorld: = "+c); }catch(Exception e ){ System.out.println("Exception is = "+e); } Here, Class c = Class.forName("OracleDriverName"); here, where the OracleDriverName is put, and from ... |
46. Why Class.forName? coderanch.com |
47. Class.forName & Import jdbc classes coderanch.comHi This is a very common scenerio that we use in any jdbc application ... Class.forName(//some jdbc.odbc class name should be declared here) now when we read the documentation of forName method it's saying that it is used to load the particular class. And the same thing we can do by import statement in the starting of the program. Now this ... |
48. reg class.forName() coderanch.com |
49. Class.forName() coderanch.com |
50. loading in Class.forName() a class from inside a jar file coderanch.com |
51. Usage of Class.forName coderanch.com |
52. class.forName coderanch.com |
53. Class.forName in depth coderanch.com |
54. Difference between DriverManger.registerDriver() and Class.forName() ? coderanch.com |
55. Class.forname and DriverManager coderanch.com |
56. Doubt on JDBC class.forname.. coderanch.com |
57. Loading jdbc driver using class.forName() coderanch.com |
58. Why Class.forName for registering driver coderanch.com |
59. question about Class.forName() java-forums.orgJDBC (for the most part) is part of the JSE . And, although the method "forName" of the class "Class" is used very often when using JDBC (for loading the Driver), the class "Class" is not part of JDBC, but rather is one of the base classes for Java itself and is, of course, part of the JSE. |
60. Class.forName java-forums.orgHi all I tried to run a sample code mentioned below and i get compilation error: cannot find symbol symbol: method forName(java.lang.String) location: class Class Class.forName(driver); This is the below code: //STEP 1. Import required packages import java.sql.*; public class FirstExample { // JDBC driver name and database URL static final String JDBC_DRIVER = "com.mysql.jdbc.Driver"; static final String DB_URL = "jdbc:mysql://localhost/EMP"; ... |
61. Class.forName( ) for loading jdbc driver forums.oracle.com |
62. Use of Class.forName() in JDBC forums.oracle.comthanks much.. ok so. calling the Class.forName automatically creates an instance of a driver and registers it with the DriverManager. When we use the string / string buffer class we dont need to explicitly load the classes exist in java.Lang package. But to get the JDBC connection, we need to insert the code Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");.. please clear my confusion. |
63. Class.forName() problem in JDBC... forums.oracle.comyou don't need to get hold of the instance of Driver yourself, generally Drivers have what's known as a static initializer - a bit like a constuctor, only not really, and for classes rather than objects - that does all the initializing of the driver, the registering of the driver with DriverManager etc. all you have to do is ensure the ... |
64. Class.forName in jdbc forums.oracle.comHi , I know this has been discussed a couple of times before however I am still not clear on this. Why do we need to do Class.forName while setting up jdbc. In case it is for loading the class , why do'nt we need it for any other class. How come hot spot JVM knows how to find the class ... |