If I can't find a sample procedure/algorithm/problem in a Processing book, ...

Can you please explain the logic of your statement/question for a simple minded person like me?

Processing language IS Java, loops are not similar, but identical!
If you use the 018x releases, you can now use Java 1.5 syntax too ( HashTable<String, Agent>, for (Agent a : agents) and so on) making even easier to pick modern examples.
Actually, it is not pure Java (if you code in Eclipse, you have to adapt a bit the code), as it removes the need to add f after float literals, implements the pseudo type color (just an int, actually), allow to use #BADBEF literals, to do int(x) or float(x), and some other facilities.

There arose a bundle of scripting languages or languages of the Java breed  or/and based on Java VM (JavaFX, Groovy, BOO and more http://java-source.net/open-source/scripting-languages) If you are looking for a language closer to java syntax than Processing, you might give Scala the youngest descendant  a try:

www.scala-lang.org/


Some professional users claim some immaturity, as there are breaks in the versions and miss backward compatibility. Scala also has a bunch of nice Ruby features, which Java lacks, including closures and "trendy" AST macros. Scala also supports threads. BTW, one can import processing.core.Papplet into Scala. Say Scala inherits all class Processing's variables and methods.

Java and that languages play at another league and another game. In such discussions/comparisons one should keep in mind that Processing is breeded to graphics and esthetics without compromis and is by no means constructed as a general purpose language!

For my taste the user interactivity is underdeveloped, say i. e. for scientific applications. Just try to read interactively a couple of mixed floats and integers and strings  given by the user in a running program.