I couldn't figure out that what is 'open' really? Is that the source code for java classes?
From that site,
Official Sun Web Site wrote:The Java community is vibrant and diverse with extensive development knowledge and expertise. Making Java technology freely available under the GPL license opens new development opportunities for free software developers and enables a new wave of innovation.
I didn't understand this at all. What is the maning of "Making Java technology freely available"? Isn't it free before (i.e. JDK)?