This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
Or do you mean the package prefixes java and javax? Most of the packages starting with javax where initially additional libraries not shipped with the JRE / JDK (e.g. Swing); they were later integrated. Package javax.activation is one of the latest packages to be included, after spending much time as part of the Java Activation Framework.