Query about jre version 1.4 or 1.7

In the sparkplug kit instructions it says:

To setup a project to run Spark within your IDE, you will need to the following:

• It is required that you use the 1.4 JRE to build Spark.

However I am sure I saw somewhere that using jre 1.7 was better for runtime. Does the 1.4 recomendation for build still apply?

Thanks

David