Understanding the significance of Java 9

Unarguably, the modularization of the Java platform, developed as part of Project Jigsaw, was the greatest change introduced to the Java platform with Java 9. Initially planned for Java 8, but postponed, Project Jigsaw was one of the main reasons why the final release of Java 9 was itself postponed. Jigsaw also introduced a few notable changes to the Java platform and was one of the reasons Java 9 was considered a major release. We will explore these features in detail in subsequent chapters.

Apart from the Jigsaw-related Java enhancement proposals, there is a long list of other enhancements that made it in Java 9. This section explores the most significant features introduced in Java 9, specifically:

• Breaking the monolith
• Using the Java Shell
• Taking control of external processes
• Boosting performance with G1
• Measuring performance with Java Microbenchmark Harness (JMH)
• Getting ready for HTTP 2.0
• Encompassing reactive programming