Description: You should confirm that your computer has the correct software installed and that the environment variables are set before you start working with Derby.
Keywords: Java Development Kit version, verifying, JDK version, Working with Derby activities, prerequisites, environment variables, JAVA_HOME environment variable, DERBY_HOME environment variable

# Verifying the Derby system configuration

You should confirm that your computer has the correct software installed and that the environment variables are set before you start working with Derby.

To check the Derby system configuration:

1. Verify that the `java.exe` file, version 1.4.2 or, higher is in your command execution PATH by opening a command window and running the `java -version` command. The output from the command looks something like this:

       java version "1.4.2_04"
       Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.2_04-b05)
       Java HotSpot(TM) Client VM (build 1.4.2_04-b05, mixed mode)

   The output you see might be different from what is shown here because the `java -version` command outputs vendor-specific information. If the command produces an error or the version listed is not 1.4 or higher, install a JDK before continuing.
2. Verify that the DERBY_HOME environment variable is set and points to the root directory of the Derby 10.4 installation. Open a command window and run the appropriate command for your system. If you installed Derby in the /opt/Derby_10 directory on UNIX or the c:\Derby_10 directory on Windows, the command that you use and the expected output are shown in the following table:

   Operating System | Command | Output
   --- | --- | ---
   UNIX (Korn Shell) | `echo $DERBY_HOME` | `/opt/Derby_10`
   Windows | `echo %DERBY_HOME%` | `C:\Derby_10`

   If you receive an error or do not see the expected output, ensure that you have set the `DERBY_HOME` environment variable, as described in Setting the environment variables.

Note: You can also use the `sysinfo` utility to verify that the environment variables are set correctly. If the environment variables are set correctly, the `sysinfo` command displays information about your Java virtual machine (JVM) and the version of Derby that you have installed.
Parent topic: Installing and configuring Derby