Java 9 - A very brief preview

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# Java 9
## A very brief preview
]

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# April 14, 2015
# September 22, 2016
# September 22, 2017
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# Project Jigsaw
## The big feature in Java 9
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.jigsaw1-image[
![Before](images/jigsaw1.png)
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.copyright[
Copyright © 2015, Oracle and/or its affiliates. All rights reserved.
]

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.jigsaw2-image[
![Before](images/jigsaw2.png)
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.copyright[
Copyright © 2015, Oracle and/or its affiliates. All rights reserved.
]

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.jigsaw2-image[
![Before](images/jigsaw3.png)
]
.copyright[
Copyright © 2015, Oracle and/or its affiliates. All rights reserved.
]

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## Modules are<br>for everyone!
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Very simple module-info.java
```
module org.example @ 1.0 {
    requires jdk.base;
    requires com.google.guava @ 18.0;
    exports org.example.api;
}
```
]
--
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```
module org.example @ 1.0 {
    requires jdk.base;
    requires com.google.guava @ 18.0;
    exports org.example.api;
*   exports com.google.common;
}
```
]

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## <span style="padding-left: 5px;">jshell, aka</span><br> the Java REPL
]
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```bash
|  Welcome to JShell -- Version 0.508
|  Type /help for help

-> System.out.println("Hello world!")
Hello world!

-> 
```
]
--
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```bash
-> (int) (Integer.MAX_VALUE + 1)
|  Expression value is: -2147483648
|    assigned to temporary variable $1 of type int
```
]
--
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```bash
-> (long) (Integer.MAX_VALUE + 1)
|  Expression value is: -2147483648
|    assigned to temporary variable $2 of type long
```
]
--
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```bash
-> (long) (Integer.MAX_VALUE + 1L)
|  Expression value is: 2147483648
|    assigned to temporary variable $3 of type long
```
]

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## Compile for Older Platform Versions
]
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```
class PrintTheArgs {
  public static void main(String... args) {
    System.out.println(String.join(", ", args));
  }
}
```

```bash
javac -source 1.6 -target 1.6 Test.java
```
]

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## New<br>Version-String Scheme
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Current scheme
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* Minor releases containing changes beyond security fixes are multiples of 20
* Security releases based on the previous minor release are odd numbers incremented by five, or by six if necessary in order to keep the update number odd
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]
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* e.g. 1.8.0, 1.8.0_5, 1.8.0_11, 1.8.0_20, 1.8.0_25, 1.8.0_31, 1.8.0_40, 1.8.0_45
]]
--

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<div style="margin: 20px 0;">
JDK 9+ scheme: MAJOR.MINOR.SECURITY
</div>
]
--
.right-column-incremental[.incremental-bullets[.narrow-bullets[
* 1.8.0 ⇒ 8.0.0
]]]
--
.right-column-incremental[.incremental-bullets[.narrow-bullets[
* 1.8.0_05 ⇒ 8.0.1
]]]
--
.right-column-incremental[.incremental-bullets[.narrow-bullets[
* 1.8.0_11 ⇒ 8.0.2
]]]
--
.right-column-incremental[.incremental-bullets[.narrow-bullets[
* 1.8.0_20 ⇒ 8.1.2
]]]
--
.right-column-incremental[.incremental-bullets[.narrow-bullets[
* 1.8.0_25 ⇒ 8.1.3
]]]
--
.right-column-incremental[.incremental-bullets[.narrow-bullets[
* 1.8.0_31 ⇒ 8.1.4
]]]
--
.right-column-incremental[.incremental-bullets[.narrow-bullets[
* 1.8.0_40 ⇒ 8.2.4
]]]
--
.right-column-incremental[.incremental-bullets[.narrow-bullets[
* 1.8.0_45 ⇒ 8.2.5
]]]

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## More Polyglot!
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Parser API for Nashorn

Java-Level JVM Compiler Interface
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## Java 10?
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Value Types
* "Codes like a class, works like an int!"
* Navigate array of value types very fast
  * Also see http://objectlayout.org
* Other optimizations become possible
  * Java 8's Optional<T> ⇒ Value Type
  * Iterators without memory allocation
* See http://www.infoq.com/presentations/java-9-10
]
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Generic Specialization
* E.g. List&lt;int&gt;
* Related to Value Types
]