EJB / EE :: GenericJDBCException - Could Not Open Connection
Oct 3, 2014
I am new to EJB; I am writing EJB (3.1) program in JBoss 7.1 - I am using MySQL DB with JPA. While executing the program, I am facing the Generic JDBCException: Could not open connection. It is happening only for certain tables in the database; but NOT for all tables. My code is able to access few of the tables in the same database. Here is my full stack trace: -
Exception in thread "main" javax.ejb.EJBException: javax.persistence.PersistenceException: org.hibernate.exception.GenericJDBCException: Could not open connection
at org.jboss.as.ejb3.tx.CMTTxInterceptor.handleExceptionInOurTx(CMTTxInterceptor.java:166)
at org.jboss.as.ejb3.tx.CMTTxInterceptor.invokeInOurTx(CMTTxInterceptor.java:230)
at org.jboss.as.ejb3.tx.CMTTxInterceptor.required(CMTTxInterceptor.java:304)
at org.jboss.as.ejb3.tx.CMTTxInterceptor.processInvocation(CMTTxInterceptor.java:190)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288)
I am trying to get RJDBC to work so I can connect to Oracle from R doing some data analysis..
This connection string works for my local db which I have it running in my Virtual Box
con <- dbConnect(drv, "jdbc:oracle:thin:@//localhost:1521/orcl", "demo", "demo")
However, it does not work when I do it for the remote db that I really need to pull data from...
> con <- dbConnect(drv, "jdbc:oracle:thin:@//ymsdbppr-scan:1522/YMQCTPRD", "user_read", "user_read")
Error in .jcall(drv@jdrv, "Ljava/sql/Connection;", "connect", as.character(url)[1], : java.sql.SQLException: Listener refused the connection with the following error: ORA-12514, TNS: listener does not currently know of service requested in connect descriptor
Now, I have got a comment saying I should get the database connection from connection pool. And one more issue is that I have used the function System.getProperty("user.name") to get the username which i have logged in. But this code will be run on Unix which will not support this function. Any function where I can get the windows username. There is a function getUserPrincipal(), but this function returns a NULL. How to resolve this.
I configured a connection pool in tomcat 7. For every database activity I get a connection from the pool. Do I have to close the connection like other regular connection after the database operation is done? If I close the connection will it have any effect on the connection pool?
how to open a GUI on top of another GUI? I have built a GUI and have a button that when pressed I want to open a new GUI which is another java application within the project, it seems pretty straight forward and I just need to insert 'new [name of application]()'
Button btnEdit = new Button(shell, SWT.NONE); btnEdit.addSelectionListener(new SelectionAdapter() { @Override public void widgetSelected(SelectionEvent e) { new edit(); } }); btnEdit.setBounds(76, 10, 75, 25); btnEdit.setText("Edit");
I was wondering if I could take the following code and somehow put the connection to database in it's own class without the "public static void main(String[] args)" method. That way I could call it anytime i want to open a connection to the database.
Java Code:
import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Statement; public class Sample { public static void main(String[] args) throws ClassNotFoundException
i have an older file I was working on 2 months ago and when i try to open it in eclipse I get a message corruption error. I know this is not possible since I was just working on it a while back, and it's the same program version as what i am currently using..Or would I do a file import instead?
Is there a way we can open a .chm file stored at server through jsp application without downloading the file and saving it to the local machine.
What I googled is : we cannot download .chm files from a web browser and simply click Open. Download the .chm file to your computer first, right-mouse click it in Windows Explorer and select Properties. Then click Unblock.
But I want my users to simply view the file without downloading it.
I'm using JSF framework. I can let Netbeans to create the persistence unit and hardcodes connection parameters into the persistence.xml file or i can use resource tag in context.xml file or using another file like property file or class for holding connection parameters like username and password; what is the most secure way or expert way to use connection properties in my app or there is no difference?
I am trying to make a simple login using netbeans, derby database included in netbeans and tomcat server. I made everything nice and separated: I have a model package with a class called DbConnector that has the following method:
Then i have another class, an userDAODB that has a password check method:
public boolean checkPassword(String user, String password) { try (Connection con = new DbConnector().connect(); Statement stmt = con.createStatement()) { //checks the password in the database
In the main method of this class i tested everything, it works very nice, logs me in, other methods work too, no problem what so ever.But then i go to my servlet:
public class LoginTest extends HttpServlet { public void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException { String username = request.getParameter("username"); String pass = request.getParameter("pass"); UserDAODB userDAO = new UserDAODB(); boolean authe = userDAO.checkPassword(username, pass);
[code]....
So when i start the webpage and i try to click on the login button I get a NullPointerException com.model. UserDAODB. check Password (User DAODB. java:14) - so line 2 here
I have been googling a bit, i placed the derby.jar and the derbyclient.jar in the lib directory of tomcat, i tried to modify the context.xml of my application, but then it wouldn't even start anymore.
I got the below exception .how to resolve this .It's receiving the data up to 10 min then suddenly below error happening. I have embedded the source code below
java.net.SocketException: Connection reset at java.net.SocketInputStream.read(Unknown Source) at java.net.SocketInputStream.read(Unknown Source) at sun.nio.cs.StreamDecoder.readBytes(Unknown Source) at sun.nio.cs.StreamDecoder.implRead(Unknown Source)
I am unable to connect my javafx scene to mysql database. I get a java.lang.NullPointerException every time. I tried searching everywhere possible but no answers available. This is the Person class (super class for Teacher class):
/* * To change this license header, choose License Headers in Project Properties. * To change this template file, choose Tools | Templates * and open the template in the editor. */
Below is a code of a simple file downloader in java. I want to detect an exception when the connection is broken in the middle of downloading a file. Now, I run the code and in the middle of downloading the file, i turn off my wifi with keyboard wifi off button. Doing this the program hangs forever without throwing any exceptions and without terminating. It seems it blocks forever.why is exception not thrown? Secondly, in the following code you can see this line //con.setReadTimeout(2000); which is currently commented out. Removing the comment and running the program, now if connection breaks in the middle by turning off wifi then it waits for 2 seconds and then if it cannot read then it terminates without throwing exception. So, again in this case why is it just terminating and not throwing any exception?
I have noticed an error, that makes sometimes troubles, when downloading jars from https addresses, when there are many jars to download..
Best example is by opening Javas on Java version checker. [URL] ....
I get also following log...
network: Connecting https://www.java.com/jsp_utils/jreverification.jar with proxy=DIRECT network: Connecting http://www.java.com:443/ with proxy=DIRECT network: Connecting https://www.java.com/jsp_utils/jreverification.jar with cookie "JSESSIONID=22ABBA2BE9B5789629C276AC35BDF969; s_cc=true;
Even if the address is https, java try to access via http protocol on port 443, and that leads sometimes to problems..
I have noticed this, when I have used URLConnection(HttpURLConnection) for my self, as soon Java sends http link on https address, the jar gets sometimes not loaded, and i get error about missing class that get called..
On http addres it is not so bad, since same protocol is used, but evidently, that is evil for https..
As you see, that happens already when loading Jar by Applet Starter and at all, it happens each time on any URLConnection
############################### Java Plug-in 10.13.2.20 Using JRE version 1.7.0_13-b20 Java HotSpot(TM) Client VM User home directory = X:Usersadmin ---------------------------------------------------- c: clear console window f: finalize objects on finalization queue g: garbage collect
What does this error mean, and also, when I get it, the command line hangs so that I can't do anything else (Is there a way to recover from that?). I'm running Windows 7.
Jan 03, 2015 5:00:59 AM java.util.prefs.WindowsPreferences <init> WARNING: Could not open/create prefs root node SoftwareJavaSoftPrefs at root 0 x80000002. Windows RegCreateKeyEx(...) returned error code 5.
i dont know how to write main that would open the input file and read using this method...
[/package AssignmentSeven; import java.io.*; import java.util.Scanner; public class Assignment7 { public static void Towers(int nTowers, int fromTower1, int workTower2, int toTower3) { if(nTowers == 1)
I was just wondering how would I create a jar file that would open 3 other jar files when I open the jar file with my batch file it and when I type stop in the batch file it will out put the stop command into all 3 of the other jar files.
This is for my Minecraft server so I can launch them all at the same time and inStead of having to enter the commands in all the server batch files I just have to do the command in 1 I know their is things like multi craft to do this but I want the code so I don't have to use multicraft.
I'm using java FX-8 and JDK 1.8,Netbeans 8.0.2.I want to open pdf on button click in my JavaFXML Application.I have triued pdf viewer plugins and iText but it doesn;t work.I have to pass variable value in pdf too.
