Java 升级到jdk7后DbVisualizer 6 启动空指针的处理方案

将JDK从6升级到了7（或从其他电脑移植DBV文件夹后），每当启动DbVisualizer 6的时候都会报空指针异常

在官网上找到了相关的方案，如下：

In the DbVisualizer installation directory there is a.install4j directory.

In this directory create a file named pref_jre.cfg if it doesn't already exist.

Open the file in a text editor

Add the complete path to the root directory for the Java installation you want to use. 

Example: C:\Program Files\Java\jre6.