Uncovering Project Amber

Mala Gupta (@eMalaGupta) Java Champion & Developer Advocate Uncovering Project
Amber

Twitter: @eMalaGupta About the presenter

Books – Manning Publications Packt Publications

Founder – eJavaGuru.com

Community Leader - Delhi Java User Group - WWCode Delhi

Java Champion

Started in early 2017 – Led by Brian Goetz

var Switch expressions Records ……. Text blocks Project Amber

Started in early 2017 – Led by Brian Goetz

Why should you care?

Recent changes

Future code?

Are there any stages?

http://cr.openjdk.java.net/~mr/jep/jep-2.0-02.html

What are release dates?

Change is constant

Change is constant Change is inevitable

Change is constant Change is inevitable Change is beautiful

It is neither the strongest nor the most intelligent that
survives. It is the one that is most adaptable to change. -Darwin

Change is painful. Ouch!

In today’s session: Delivered: Type inference with ‘var’(Java 10) Local-Variable
Syntax for Lambda Parameters (Java 11) Switch Expressions (Java 12) Coming soon: Old: Raw String Literals, Now: Text Blocks (Java 13) (Updated) Switch Expressions (Java 13) Yet to be released: Pattern Matching (https://openjdk.java.net/jeps/305) Old: Data classes, Now: Records and Sealed Types (https://openjdk.java.net/jeps/8222777) Enhanced enums (http://openjdk.java.net/jeps/301) Concise Method Bodies (https://openjdk.java.net/jeps/8209434)

Twitter: @eMalaGupta Type Inference with ‘var’ (Java 10)

Twitter: @eMalaGupta Demo

Twitter: @eMalaGupta Where you can and can’t use var

Twitter: @eMalaGupta Check

Twitter: @eMalaGupta Is this okay?

Twitter: @eMalaGupta Type inference with derived classes

Twitter: @eMalaGupta Inheritance & Method return type

Twitter: @eMalaGupta Local variable syntax for lambda parameters (Java 11)

Twitter: @eMalaGupta Switch expressions (Java 12)

Twitter: @eMalaGupta Text Blocks (Previously - Raw String Literals) Releasing
with Java 13

Text Blocks <HTML> <BODY> <H1>Meaning of life</H1> </BODY> </HTML>

Text Blocks String html = "<HTML>\n\t<BODY>\n\t\t<H1>Meaning in life</H1>\n\t</BODY>\n</HTML>";

Text Blocks String html = "<HTML>" + "\n\t" + "<BODY>"
+ "\n\t\t" + "<H1>Meaning of life</H1>" + "\n\t" + "</BODY>" + "\n" + "</HTML>";

Text Blocks Try the following – with and without text
blocks: (\w)(\s+))[\.] {"plastic": { "id": "98751", "singleuse": { "item": [ {"value": "Water Bottle", "replaceWith": "Steel Bottle()"}, {"value": "Straw", "replaceWith": "Ban Straws"}, {"value": "Spoon", "replaceWith": "Steel Spoon"} ] } }}

Text Blocks String html = """<HTML> <BODY> <H1>Meaning of life</H1>
</BODY> </HTML> """;

Twitter: @eMalaGupta Records

Records and changes to JLS http://cr.openjdk.java.net/~gbierman/8222777/822 2777-20190823/specs/records-jls.html Caution: This is
a work in progress and can change without notice.

Twitter: @eMalaGupta Sealed Types (classes, abstract classes, or interfaces)

Twitter: @eMalaGupta Concise Method Bodies (Draft stage)

Future code?

Twitter: @eMalaGupta Pattern matching

Object obj = new Ocean(); if (obj instanceof Ocean) {
System.out.println(((Ocean)obj).getBottles()); }

Object obj = new Ocean(); if (obj instanceof Ocean) {
Object ocean = (Ocean)obj; System.out.println(ocean.getBottles()); }

Object obj = new Ocean(); if (obj instanceOf Ocean o)
{ // LINE 1 System.out.println(o.getBottles()); } else { // can’t use o defined at line1 here }

Type Test Pattern

Twitter: @eMalaGupta Enhanced Enums (Currently on hold)

Enhanced enums (Currently on hold) enum Size {SMALL, MEDIUM, LARGE}

Enhanced enums (Currently on hold) enum Size { SMALL(36, 19),
MEDIUM(32, 20) { int number = 10; int getSize() { return length + width; } }, LARGE(34, 22); int length; int width; Size(int length, int width) { this.length = length; this.width = width; } int getLength() { return length; } }

Enhanced enums (Currently on hold) System.out.println(Size.MEDIUM.number); System.out.println(Size.MEDIUM.getSize());

Enhanced enums (Currently on hold)

Enhanced enums (Currently on hold) enum Size <T extends Measurement>
{ // enum with type parameter SMALL(new Small()), MEDIUM(new Medium()), LARGE(new Large()); private T mObj; Size(T obj) { mObj = obj; } T getMeasurement() { return mObj; } }

Enhanced enums (Currently on hold) class Measurement {} class Small
extends Measurement { String text = "Small"; } class Medium extends Measurement {} class Large extends Measurement { public int getLength() { return 40; } }

Enhanced enums (Currently on hold) var large = Size.LARGE; System.out.println(large.getMeasurement().getLength());

Enhanced enums (Currently on hold) Let’s say you want to
code something like the following: FormData data = new FormData(); data.add(Data.NAME, "Pavni"); data.add(Data.AGE, 22); data.add(Data.ADDRESS, "California");

Enhanced enums (Currently on hold) public enum Data<T> { NAME<String>,
// constants of generic AGE<Integer>, // enum Data ADDRESS<Address>; }

Enhanced enums (Currently on hold) public class FormData { public
<T> void add(Data<T> type, T value) { //..code } }

Enhanced enums (Currently on hold) FormData data = new FormData();
data.add(Data.NAME, "Pavni"); data.add(Data.AGE, 22); data.add(Data.ADDRESS, "California");

Change is constant – embrace it.

Mala Gupta Developer Advocate @ JetBrains Java Champion, Book Author
Founder eJavaGuru.com Twitter: @eMalaGupta

Uncovering Project Amber

Uncovering Project Amber

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