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Java Database Q&A » mysql » connection 1 

1. Should I be using PreparedStatements for all my database inserts in Java?

What is the recommended method for escaping variables before inserting them into the database in Java? As I understand, I can use PreparedStatement.setString() to escape the data, but PreparedStatement seems somewhat impractical ...

2. Is JDBC Connection aquiring with MySQL slower than with e.g. Derby?

I use

  • Tomcat
  • C3p0 (JNDI configured inside Tomcat)
  • MySQL(InnoDB) / Derby(not embedded) as Database
  • EHCache (in Memory)
  • Hibernate
  • Testmachine runs WinXP
I used Derby for development and wanted to switch to MySQL. I was surprised to see, that with ...

3. webservice: error in code or connection

I have a problem in my code or connection I think... I tried to connect to a MySQL database and web service, but when I run the program, it gives me the ...

4. Using Prepared Statements and Connection Pooling together in MySQL

Presently, for each query, a Prepared Statement is created and reused. I am not using any connection pool. C3P0 is a widely recommended library for the same. But, as a ...

5. What is the best way/template to set up connection mysql and jdbc?

What is the best way to set up connection with mysql's jdbc? And execute simple statement. How to do that? Thank you.

6. jdbc4 CommunicationsException

I have a machine running a java app talking to a mysql instance running on the same instance. the app uses jdbc4 drivers from mysql. I keep getting com.mysql.jdbc.exceptions.jdbc4.CommunicationsException at random ...

7. Optimal number of connections in connection pool

Currently we are using 4 cpu windows box with 8gb RAM with MySQL 5.x installed on same box. We are using Weblogic application server for our application. We are targeting for ...

8. isValid() call never returns on MySQL JDBC Connection

I have trying to check whether connection is valid or not and using isValid() method of java.sql.Connection. But this method doesn't return and hangs. Is there anything I am missing or ...

9. Java mysql connection time

I have a java program running 24/7. It accesses mysql database every 3 seconds only from to 3.PM. In this case when should I should open and close the MySql ...

10. Java-Mysql Connection error

My stack trace:

cbs.ui.OverallReportUI btnGenerateBillActionPerformed
SEVERE: null
java.sql.SQLException: Access denied for user 'root'@'localhost' (using password: YES)
        at com.mysql.jdbc.SQLError.createSQLException(
        at com.mysql.jdbc.SQLError.createSQLException(

11. ClientAbortException: Connection reset by peer: socket write

I am using MySQL 5.1 and my connector version is mysql-connector-java-5.1.7. I am getting following exception frequently. What is the issue?

Dec 24, 2009 10:29:20 AM org.apache.catalina.core.StandardHostValve status
WARNING: Exception Processing ErrorPage[errorCode=404, location=/error.jsp]
ClientAbortException: ...

12. Can't make JDBC connection to MySQL (using Java, IntelliJ, and Linux)

I am having issues trying to get a database connection using the code below:

  try {

13. Jetty mysql connection-pool configuration error: javax.naming.NameNotFoundException; remaining name 'env/jdbc/---(mysql 5.0+jetty 7.0.1)

My configuration files project/WEB-INF/web.xml:

    <description>ConnectionPool DataSource Reference</description>
<New id="mysql" class="">

14. Establishing persistent connection to a database in Java

I've ran through several examples over the web, and found that every single time I need something from the DB, I should write the following code:

  // Step 1: Load ...

15. Jetty 7 + MySQL Config [java.lang.ClassNotFoundException: org.mortbay.jetty.webapp.WebAppContext]

I've been trying to get a c3p0 db connection pool configured for Jetty, but I keep getting a ClassNotFoundException:

2010-03-14 19:32:12.028:WARN::Failed startup of context WebAppContext@fccada@fccada/phpMyAdmin,file:/usr/local/jetty/webapps/phpMyAdmin/,file:/usr/local/jetty/webapps/phpMyAdmin/
java.lang.ClassNotFoundException: org.mortbay.jetty.webapp.WebAppContext

16. stored procedures, error #1312, CLIENT_MULTI_RESULTS flag

i am writing stored procedures in MySQL that return values;

CREATE PROCEDURE getCustomerById (id int)
    FROM customer
 WHERE = id;
and i get the error that the ...

17. java jdbc connection to mysql problem

I am trying to connect to mysql from java web application in eclipse.

 Connection con = null; 

  try {
    //DriverManager.registerDriver(new com.mysql.jdbc.Driver());

18. Java / MySQL - How to access connection from another class?

I'm just getting my head around java (and OOP for that matter), the only thing I am familiar with is MySQL. I need to keep the DB connection open throughout the ...

19. Netstat shows numerous CLOSE_WAIT states for mysql connections

The output of netstat -an shows many mysql connections in CLOSE_WAIT state and when i checked the processlist in mysql using 'SHOW PROCESSLIST' the connections shown in netstat do not appear. ...

20. Failed to execute stored procedure from the JDBC code using mysql connection

I have one database. I executed a stored procedure on it. I wrote some JDBC code to connect to this database. When I am calling this stored procedure from my JDBC ...

21. How to check the Database Connection leakage in J2EE application?

Is there anyway to check the Connection leakage in J2EE application ? The application is running on my local machine. It uses MySQL database. User Enters his details into the Database. In my ...

22. What files needed for JDBC connection to MySQL?

I get the following error when attempting to connect to the MySQL database on my employer's local server:

Unable to load database driver Details : java.lang.ClassNotFoundException: com.mysql.jdbc.Driver BUILD ...

23. Does MySql support connection pooling for Java SE applications?

From the examples that I have read and from the documentation on MysqlConnectionPoolDataSource at it seems that Java SE applications cannot use connection pooling. Is this true? Can ...

24. Does the setting time_out in mysql affect JDBC connection pool?

It's usually set to 60 seconds. But I think con pool will hold the connection, so is there any conflict? Thank you.

25. MySQL connection using DefaultHttpClient

I've tried to connect to mysql using DefaultHttpClient, but so far no success. Error connection refused. I can telnet MySQL using telnet 3306 enter code here I'am using this example from apache website

DefaultHttpClient ...

26. Connection Time Out JDBC-MySQL

I have a Java application running Win 7 connecting to MySQL on the same host. Eclipse IDE shows the following error every time after 8-10mins. The ...

27. Java newbie needs help with database connection

I'm new to Java but even newer to java database connections. I've managed to create a database connection and query a table when I put it in the Main class. Now ...

28. Java FX and Database Connection

I want to write a JavaFX program with Database Connection(MYSQL). I did not know how to create a connection in program. And the methods I found on internet is not working ...

29. I want to give JDBC connection to mysql. I dont wish have the data values inside my class people()

 import java.util.*;
 import org.directwebremoting.util.Logger;
 public class People
public People()
    people = new HashSet();
    random = new Random();
    log.debug("Generating a new set of ...

30. Java - JDBC connection

I am getting this error:

       FOR REAL Looking for database...
com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The ...

31. Unix socket connection to MySql with Java to avoid JDBC's TCP/IP overhead?

Is it possible to make a Unix socket connection to MySql with Java to avoid JDBC's TCP/IP overhead? Does anyone know a library (or a few libraries, perhaps) that makes this possible? ...

32. Basicdatasource connection time out problem (using mysql)

I am using BasicDatasource in my application. This application is processing huge amount of raw data. Sometimes 1 query can take more than 15 minutes. (using mysql as db) Here is my ...

33. Incorrect Use of JDBC Connection Pool

I am running a Spring MVC application, backed by a MySQL database which I am accessing using JDBC. I have been using the same code for a while, and have never ...

34. Java autogenerated MySQL database connection encoding

i have a Java project connected to a MySQL database.
When I communicate between the two using executeQuery(query) everything seems to be fine with the encoding, BUT I have some autogenerated CRUD ...

35. How to make a MySQL Connection in JAVA

I can't seem to get a connection made on my Java program to java, I have started the MySQL Server, made a database in phpMyAdmin. But I'm confused on how I ...

36. A persistent connection with JDBC to MySQL

I have an application that connects to MySQL using JDBC. There are cases where the JDBC connection lies idle for hours (maybe even days) and its loosing its connection to ...

37. MysqlDataSource Invokes "Connection refused" Exception

Here is a part from my program:

try {
        InitializeData data = new InitializeData();


38. MySQL connection in Java problem

I try to get some data form database. The connection method works for sure, but I have a problem getting any data form DB:

    SQLConnect s = new ...

39. Java Netbeans: Editing the MySQL DB connection infos

I just created a new project with NetBeans using the database template to connect to a MySQL database. After searching a while I got a question and hope anyone can help ...

40. JDBC connection- Class.forName vs Class.forName().newInstance?

Was wondering why both Class.forName("com.mysql.jdbc.Driver"); and Class.forName("com.mysql.jdbc.Driver").newInstance(); work when i use them to connect to a database. By right, isn't the former not supposed to work, since no new instance was ...

41. MySQL with Java: Open connection only if possible

I'm running a database-heavy Java application on a cluster, using Connector/J 5.1.14. Therefore, I have up to 150 concurrent tasks accessing the same MySQL database. I get the following error:

Exception in ...

42. in mysql jdbc does auto commit affect all connections?

when using a connection pool, will setting a connection's autocommit = false affect this connection only? if i close this connection without setting autocommit = true and get a new connection will this connection's policy ...

43. mysql java connection error

I am running my JAR file in linux (centos). All jar files work fine. Now i am trying to connect to mysql server, but it gave me following error.

Exception in thread "main" ...

44. database connection ClassNotfoundException

Whenever I execute my code for accessing a database I get the following error:

:java.lang.ClassNotFoundException: com.mysql.jdbc.DriverError :java.lang.ClassNotFoundException: com.mysql.jdbc.Driver

45. Closing JDBC Connections in Pool

Our standard code section for using JDBC is...

Connection conn = getConnection(...);
Statement  stmt = conn.conn.createStatement (ResultSet.TYPE_SCROLL_INSENSITIVE,

46. MySQL and JDBC Connection Pool: unclosed statements

I am reviewing a big pile of existing code, trying to find unclosed connections that would cause the connection pool to run out or throw other erros. In some places I see ...

47. JBoss connection pool creating many connections to MySQL

We are using a setup of JBoss 4.2.2.GA / Hibernate 3.2.4.sp1 / SpringMVC 2.5 / MySQL 5.0.27. Below is the mysql-ds.xml file:


48. MySQL : Communication Link failure error and telnet localhost 3306 : Connection close

Im trying to connect MYSQL db using Java where my SQL db is on localhost. Im facing some issues regarding communication link failure.

public testfile() throws ClassNotFoundException, SQLException{


49. MYSQL resetting the connection

I am using CAS 3.4.5 on Apache tomcat 6 webserver with backend being mysql 5.1.37. I am connecting from CAS which is written in Java spring framework to Backend using mysql-jdbc-connector version ...

50. jdbc connection using mysql

 import java.sql.*;

    public class MysqlConnect{

      public static void main(String[] args) {

        System.out.println("MySQL Connect Example.");


51. JAVA MySQL Connection ClassNotFound Exception

package cs352hw;
import java.sql.Connection;
import java.sql.DriverManager;
public class Main {
   public static void main(String[] args) {
    // TODO code application logic here
      DB db ...

52. Java and MySql connection problem

I am using Java+MySql. I am trying to add bulk data (around 40 million records). My application works fine for couple of hundred thousands records but after that it starts giving ...

53. Java Connection to DB

I am having a slight problem here. basically I want to create a connection pool to DB using a class. This pool can be usable by other classes to execute queries. I ...

54. Jetty 7 + MySQL Config [java.lang.IllegalArgumentException: Object is not of type class org.eclipse.jett y.webapp.WebAppContext]

I've been trying to get a c3p0 db connection pool configured for Jetty (7.4.1.v20110513), but I keep getting a java.lang.IllegalArgumentException :

C:\jetty7>java -jar start.jar
2011-05-29 00:29:51.843:INFO::jetty-7.4.1.v20110513
2011-05-29 00:29:51.875:INFO::Deployment monitor C:\jetty7\webapps at interval 1

2011-05-29 00:29:51.890:INFO::Deployable ...

55. Java app handling for connections getting dropped

My app seems to be hanging overnight because of the connection getting dropped(I think that's the problem.) How can I structure my app so that it can try to roll up ...

56. database connection not working in jar, but does work in eclipse

I have created a simple database in MYSQL, which I am trying to pull data from in a java program written in Eclipse. When I run the program in eclipse, ...

57. How to create a mysql persistent connection from a java application?

Hi I'm writing a java application which needs to create a persistent connection with a mysql database. I don't have access to the database server so I can't change anything on ...

58. MyBatis - connection to MySQL randomly dropping

*UPDATE: I found a method which didn't close the session after openning. I think this might be the cause. Will test and report later. * We are using MyBatis with our GWT ...

59. Specifying TCP protocol in JDBC to mysql connection

How do you specify that the JDBC connection to mysql in the typical line

DriverManager.getConnection(url, username, password);
is via TCP? Thanks

60. JDBC MYSQL Connection without specifying database?

I am using the SphinxQL MySQL client which stores indexes as "tables" but has no real notion of a "database"...One specifies the port (9306 in my case) at which the sphinx ...

61. How to enable JDBC/MySqlConnectorj connection pooling?

I am still newbish to java development as I am mainly a C# developer. I'd like to know how to use or enable connection pooling when I do SQL requests from ...

62. JDBC/Connectorj: Understanding connection pooling

I think I need to understand the concept of connection pool a bit better. I'm working in java with ConnectorJ and I deploy my servlet on a Apache Tomcat server. I've ...

63. What value specify to creating new connection on MySql workbench

i have installed MySql workbench. i want to create a database in MySql. when i click New connection, it open a dialog, there are following default values: - in connection method: there are ...

64. Is a MySql connection with Broken Pipe or EOFException = null?

Just curious, does a MySql connection with Broken Pipe or EOFException = null? I'm asking cause it might be causing a logic error in my code. Or is there a way to ...

65. JDBC - XAMPP (MySQL db) - Connection problem through internet

How to connect MySQL db from another computer through internet. Where we can specify the configurations. my.ini does not work?

66. jetty-maven-plugin JNDI JDBC Connection Problem

I need help. I've got a Maven 3.0.3 project configured to run my webapp in Jetty for integration testing. The problem I'm having is that if I start jetty ...

67. JDBC connection to sourceforge's mysql database

How do you specify that the JDBC connection to mysql in the typical line

DriverManager.getConnection("jdbc:mysql://", "user", "pass");
I requested the remote access from sourceforge but using the given port 4040 i no able ...

68. Solr indexing process: keep a persistent Mysql connection throu all the indexing process

I wrote my custom update handler for my solr installation, using jdbc to query a mysql database. Everything works fine: the updater queries the db, gets the data i need and ...

69. Problem with static variables in java

I am using static variables pretty much heavily in my application. Now after the application status is finished I am facing a problem in garbage collection. The variables that are declares ...

70. Get and SET Database Server Connection Variable with JDBC

When i open a JDBC connection to a MySQL database i want to set some database server variable, so for example every time that a connection is established i want to ...

71. Bone CP a new jdbc connection pooling library

I experienced some weird problem using MySQL connection pool in resin application server. Earlier I used Connector-J supplied connection pool manager com.mysql.jdbc.jdbc2.optional.MysqlConnectionPoolDataSource in my web application. I observed that upon concurrent connection ...

72. Java MySQL - Named Pipe connection throws warning on close

I am connecting to MySQL in Java with Connector/J using Named Pipes. My connection and query are successful, but I am receiving a warning when I try to close the connection. ...

73. Am I Using JDBC Connection Pooling?

I am trying to determine if I am actually using JDBC connection pooling. After doing some research, the implementation almost seems too easy. Easier than a regular connection in fact so ...

74. How to change mysql timezone in java connection

Mysql run at GMT+8 but tomcat run at GMT. when save datetime to database, seem run ok, when i check the datetime value in DB, i see the GMT value. But when I ...

75. connection to mysql server from clojure

I'm trying to connect to a mysql database from clojure. I'm using the example code taken from: but I'm getting this error:

com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
Last packet sent to the ...

76. Slackware 12 Really Slow JDBC

Greeting, I've some problem with JDBC, it is so slow its unbeliveble. Same code works perfect with Windows connection to a remote Database. But with slackware, it takes like 30 seconds to connect, ...

77. Java mysql jdbc connection using ipv6

This is my first time try to connect to mysql using ipv6 host connection but it always return communication link failure. Can anyone suggest to me how to do that using ...

78. C3p0 specify max and min Idle connections

DBCP let's you specify a min and max number for Idle connections See Link I can't find a similar option in C3p0. I can specify a max and min pool ...

79. Why do I need to flush the connection pool each time I redeploy?

enter image description here Made my own dual familiar with the one on Oracle.
    x VARCHAR(1)

INSERT INTO dual(x) VALUES('y');

I have ...

80. logback and mysql Connections could not be acquired

I am using logback and mysql like this:

<appender name="db" class="ch.qos.logback.classic.db.DBAppender">
    <connectionSource class="ch.qos.logback.core.db.DataSourceConnectionSource">
        <dataSource class="com.mchange.v2.c3p0.ComboPooledDataSource">

81. Creating JDBC Connection in SOAPUI

I am new to SOAPUI and have been trying to do query and procedure testing using SOAPUI. I went through the SOAPUI documentation on net however I am not able to ...

82. establishing mysql/java/jdbc connection in runtime eclipse applications

i am making a swing based desktop application that is initiated through a menu command in a runtime esclipe application.

  • let me define the flow...
aC = main eclipse application project that ...

83. Java - JDBC - MYSQL connection

I'm trying to connect to a server program i'm writing which I want it to connect to a MySQL DB and extract or insert information. I'm having a lot of trouble ...

84. How to save time when opening JDBC MYSQL connections

I have a very short Java application that just opens a connection to a remote MySQL database, reads some data, prints it, and exits. The most time-consuming part of the application ...

85. Single transaction using multiple connections. (MYSQL/JDBC)

The application I'm working on is a Java-based ETL process that loads data into multiple tables. The DBMS is Infobright (a MYSQL-based DBMS geared for data warehousing). The data loading should be ...

86. How to make a successful connection to MySQL Database

Hi NewJavaProgrammer! Welcome to! ...However, when I use Java code to make a connection, I get the following exception message: Exception:com.mysql.jdbc.Driver I'm sure, that isn't the complete error you get, ...

87. how to resolve Connection to mysql database from jApplet on webpage

hi everyone,here is the way to connect to database from japplet on webpage if we are using netbeans ide the solution will be simple. just we need to sign the applet ...

88. datbase connection with mysql and deploy in mobile

hiiii hello friends... pls help me.. me r new users to develop a new application with j2me using net beans IDE. pls help me to how to connect database with milet ...

89. MySQL And NetBeans Connection

Hi. On my NetBeans database session, I have configured an MySQL instance. The instance is running. The configurations are correct. I have already commented the skip-network of my.cnf. I am in ...

90. Connection Problems between Netbeans 6.8 and Mysql

Hello everyone, I have an application in netbeans 6.8 to connect to Mysql when I get a series of mistakes, I need help because they can not find the error. thanks ...

91. MySQL Connection:Name of Connection object?

I am attempting to connect from Netbeans to MySL using the New Connection Dialog (from Services)IE NOT USING CODE.I have installed the connector. Following is the data filled in the dialog ...

92. problems with mysql connection

Hi, I cannot see the mysql under databases in netbeans. Here is the history of how my managed to get into trouble.. Initially I had earlier version of Netbeans installed. I ...

93. XAMPP mysql connection error in netbeans

Hi guys plz help me out, I've been googling this problem for two days and still don't have a clue I installed XAMPP and netbeans 6.9 on windows 7, the problem ...

94. Making a CORRECT MySQL Database Connection??

Please forgive my ignorance as I am new to learning these applications. I need help understanding how to create a database connection based on MY particular MAMP (Mac, Apache, MySQL, PHP) set up. Netbeans (6.9.1) and Zend Studio automatically creates the following as the database URL: jdbc:mysql://localhost:3306/database name This connection above finds old databases that I created but no longer use. ...

95. MySQL Connection Stops, not showing any exception

public Connection conectar(String base) { try { Class.forName("com.mysql.jdbc.Driver").newInstance(); /*Stops when reach next line >>>*/ ...

96. MySQL - netbean connection error SOLVED

com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server. at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance( at sun.reflect.DelegatingConstructorAccessorImpl.newInstance( at java.lang.reflect.Constructor.newInstance( at com.mysql.jdbc.Util.handleNewInstance( at com.mysql.jdbc.SQLError.createCommunicationsException( at com.mysql.jdbc.MysqlIO.( at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly( at com.mysql.jdbc.ConnectionImpl.createNewIO( at com.mysql.jdbc.ConnectionImpl.( at com.mysql.jdbc.JDBC4Connection.( at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance( at sun.reflect.DelegatingConstructorAccessorImpl.newInstance( at java.lang.reflect.Constructor.newInstance( at com.mysql.jdbc.Util.handleNewInstance( at ...

97. Java NetBeans & MySQL Connection

98. How can I keep the MySQL connection always alive?

I use MySQL as my DB. When I did not schedule or fire a job for a long time, the DB connection will be closed. Then I get an exception: java.sql.SQLException: No operations allowed after connection closed.Connection was implicitly closed due to underlying exception/error: ** BEGIN NESTED EXCEPTION ** com.mysql.jdbc.CommunicationsException MESSAGE: Communications link failure due to underlying exception: ** BEGIN NESTED ...

99. Mysql - connection Configuration

I have problem I run JDBC Request to myslql database when I put in filed : JDBC Driver class : com.mysql.jdbc.DriverI have in Jmeter.log : jmeter.protocol.jdbc.config.DataSourceElement: Could not load driver: com.mysql.jdbc java.lang.ClassNotFoundException: com.mysql.jdbc at$ at Method) ...

100. mysql refused rmi connection  | Contact Us | Privacy Policy
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