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Asked: 2026-05-26T08:51:56+00:00

I’m new to java and Oracle connection I can’t establish a connection from java/tomcat

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I’m new to java and Oracle connection I can’t establish a connection from java/tomcat service to Oracle database.

I’m using Java JDK 1.7 and Oracle Version:

Oracle Database 10g Express Edition Release 10.2.0.1.0 - Product 
PL/SQL Release 10.2.0.1.0 - Production 
CORE 10.2.0.1.0 Production 
TNS for 32-bit Windows: Version 10.2.0.1.0 - Production 
NLSRTL Version 10.2.0.1.0 - Production

I added a CLASSPATH to the Environment Variables (Windows Server 2003)
C:\oraclexe\app\oracle\product\10.2.0\server\jdbc\lib\*

I also added the JAVA bin to PATH and JAVA_HOME (used by TOMCAT)

In this folder there are only two files: ojdbc14.jar and ojdbc14_g.jar

My java Code:

       import java.sql.*;
       ....
       ....

                        try
                        {                              
                                System.out.println("0");
                                Class.forName("oracle.jdbc.driver.OracleDriver");
                                System.out.println("1");
                                Connection conn = DriverManager.getConnection(
                                  "jdbc:oracle:thin:@//127.0.0.1:1521/xe",
                                  "username", "password");
                                System.out.println("2");                       
                        }
                        catch (Exception e)
                        {
                                //e.printStackTrace();
                            System.out.println("exc");
                        }

Output: (It seems that he throw an exception on Class.forName

0
exc
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1 Answer

  1. Editorial Team

    Tomcat, and all Java EE app servers, completely ignore your CLASSPATH environment variable. Same for IDEs. I don’t have one on any machine that I use.

    You should not be altering any scripts to do this, either.

    Every Java EE app server has a hierarchy of class loaders.

    The first to run is the bootstrap class loader.

    Next is the server class loader. The right place for those JARs is the Tomcat server /lib directory. The /lib directory contains all the JARs that are common to all deployments. They’re loaded before the WAR files on startup.

    There’s a class loader for each WAR file deployed. After the server class loader runs, Tomcat treats all the JARs that you put in the WEB-INF/lib and all the .class files you put under WEB-INF/classes as your project CLASSPATH.

    Once you’ve gotten that to work, the next thing is to learn about how to use JNDI lookups. The code you posted isn’t a good idea. Let Tomcat manage a connection pool for you.

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