doc.FAQ.WhatDoINeedToEstablishASingle-TierJDBCConnection You need to install one of Sun's Java Runtime Environments (JRE) on the machine that contains your client application. You need to install one of OpenLink 's .jar files on the machine that contains your JAVA client application. (The JAVA version of the .jar should match the JAVA version of the JRE.) You need to ensure that a functional database native client is installed on the machine that contains the application and the Single-Tier .jar.