This doesn’t really apply to personal use of Java but mainly if you develop and sell something. (As far as I understand it). The Register says,

Oracle is massively ramping up audits of Java customers it claims are in breach of its licences – six years after it bought Sun Microsystems.

A growing number of Oracle customers and partners have been approached by Larry Ellison’s firm, which claims they are out of compliance on Java.

Java SE is free but Java SE Advanced Desktop, Advanced and Suite are not. Java SE Suite, for example, costs $300 per named user with a support bill of $66; there’s a per-processor option of $15,000 with a $3,300 support bill. Java SE comes with the free JDK and JRE, but Advanced Desktop, Advanced and Suite layer in additional capabilities such as Java Mission Control and Flight Recorder also known as JRockit Mission Control and JRockit Flight Recorder.

Java SE is free for what Oracle defines as “general purpose computing” – devices that in the words of its licence cover desktops, notebooks, smartphones and tablets. It is not free for what Oracle’s licence defines as “specialized embedded computers used in intelligent systems”, which Oracle further defines as – among other things – mobile phones, hand-held devices, networking switches and Blu-Ray players.

Oracle finally targets Java non-payers – six years after plucking Sun
Java.com