This week's book giveaways are in the iOS and Features new in Java 8 forums. We're giving away four copies each of Barcodes with iOS: Bringing together the digital and physical worlds and Core Java for the Impatient and have the authors on-line! See this thread and this one for details.
Portal and portlets are generic concepts. Java portlet technology is a JSR standard, which means that you can deploy your portlets on any portlet container which is JSR 168/286 complaint. Some portlet containers support building portlets in different programming languages like PHP, Groovy, and so on.
If you look at iGoogle, it doesn't use Java portlet technology to aggregate content from different sources like YouTube, Gmail, and so on.