public static boolean isClassDefined(String classname) {
        try {
            Class.forName(classname, false, JDBCEnvironment.class.getClassLoader());
            return true;
        }
        catch (ClassNotFoundException e) {
            return false;
        }
    }
Returns whether the given Java class is defined within the classpath.

@param classname
    The name of the Java class to check.

@return
    true if the given Java class is present within the classpath, false
    otherwise.
extensions/guacamole-auth-jdbc/modules/guacamole-auth-jdbc-base/src/main/java/org/apache/guacamole/auth/jdbc/JDBCEnvironment.java