I wrote a thorough introduction to Project Jigsaw. In the recommended order (which is different from their publication order) these are:
Motivation And Goals Of Project Jigsaw#postA look at how Project Jigsaw (coming in Java 9) aims to solve JAR/classpath hell and at its goals to improve security, maintainability and performance.
The Features Project Jigsaw Brings To Java 9#postA detailed presentation of the features Project Jigsaw brings to Java 9: modularization, encapsulation, configuration, performance, and more.
How Java 9 And Project Jigsaw May Break Your Code#postWith Java 9 comes Project Jigsaw - a modularization of the JDK - which will break existing code. An overview over the planned changes lets you see whether yours is affected.
Jigsaw Hands-On Guide#postA Jigsaw tutorial explaining how to create modules, state dependencies between them, and use the module system as a service locator to decouple modules.
Then there are a bunch more posts on the topic that can be read in pretty much any order:
Java 2077#postThe year is 2077, the Java version is 128. It's not LTS. Here's how Loom, Valhalla, Panama, Leyden, Amber, and Jigsaw pushed humanity to the brink. And how you can save us.
Reflection vs Encapsulation#postReflection wants to break into all code; encapsulation wants to give modules a safe space. How can this stand off be resolved?
SPJCN II: What's Taking So Long?#postIn the second issue of SitePoint’s Java Channel Newsletter (from September 23rd 2016) I wonder why Java 9 takes so long.
JDeps Maven Plugin 0.2 Released#postWith v0.2 the JDeps Maven Plugin allows the creation of flexible exceptions from build-breaking for a self-paced preparation for Java 9 and Project Jigsaw.
Six-Month Delay Of Java 9 Release#postMark Reinhold proposed a six-month delay of JSR 376 / Project Jigsaw and thus of the Java 9 release. According to this JDK 9 would come out in March 2017.
JavaOne 2015: Under The Hood Of Project Jigsaw#postJavaOne 2015 saw a series of talks by the Project Jigsaw team about modularity in Java 9. This one gives a peek under the hood discussing layers and class loaders.
JavaOne 2015: Advanced Modular Development#postJavaOne 2015 saw a series of talks by the Project Jigsaw team about modularity in Java 9. This one details different migration scenarios.
JavaOne 2015: Introduction to Modular Development#postJavaOne 2015 saw a series of talks by the Project Jigsaw team about modularity in Java 9. This one introduces the basic concepts.
JavaOne 2015: Prepare For JDK 9#postJavaOne 2015 saw a series of talks by the Project Jigsaw team about modularity in Java 9. This one explains how to prepare for it.
All About Project Jigsaw On InfoQ#postMy posts about Project Jigsaw got polished and published on InfoQ.
JavaFX, Project Jigsaw and JEP 253#postJEP253 aims to prepare JavaFX for Project Jigsaw by defining public APIs for functionality that will become inaccessible due to modularization.