The following describes selected improvements of the Java API. See the Java 9 release notes.

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We can take (accept) stream elements matching a predicate.

We can drop stream elements matching a predicate.

Generate a stream using an iteration.

The following describes selected improvements of the Java language. See the Java 9 release notes.

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An interface can now have private methods. These can simplify implementing default methods.

Before Java 9 a variable referencing a resource had to be redeclared (and assigned) in the try block in order to be automatically closed.

Variables that are effectively final can be used in a try with resource block (and don’t have to be redeclared).

It is now possible to create pre allocated hash maps and hash sets through a set of new factory methods on Set and Map implementations.