JDT Embraces Java 8

Stephan HerrmannCommitter:– Object Teams– JDT

8

Java 8 ready

© 2014 by Stephan Herrmann; made available under the EPL v1.0

Eclipse DemoCamp 2014, Munich, Germany

JDT Embraces Java 8 - © 2014 by Stephan Herrmann; EPL v1.0 #2

THE RETAIL APPLICATION Company– POS– Store Integration– Mobile Devices– ...

© 2014 by Stephan Herrmann; made available under the EPL v1.0

Eclipse DemoCamp 2014, Munich, Germany

...

Domain Specific Languages

Java (Server & Client)

Hardware Integration

Schöneck, VogtlandSt. Ingbert, Saarland

BerlinKöln

JDT Embraces Java 8 - © 2014 by Stephan Herrmann; EPL v1.0 #3

● Jay Arthanareeswaran● Anirban Chakarborty● Manoj Palat● Shankha Banerjee● Manju Mathew● Noopur Gupta● Deepak Azad● Srikanth Sankaran

● Andy Clement● Steve Francisco● Michael Rennie● Olivier Thomann● Curtis Windatt

● Walter Harley● David Williams ● Dani Megert

● Markus Keller

Java 8 Support: Luna ~ “SR1”

Released March 18th!

● Jesper S. Møller

● Stephan Herrmann

JDT Embraces Java 8 - © 2014 by Stephan Herrmann; EPL v1.0 #4

Eclipse and Java™ 8

● Java 8 features supported: – JSR 308 - Type Annotations.

– JEP 120 - Repeating Annotations.

– JEP 118 - Method Parameter Reflection.

– JSR 269 - Pluggable Annotation Processor API & javax.lang.model API enhancements for Java 8.

– JSR 335 – Lambda Expressions● Lambda expressions & method/constructor references● Support for “code carrying” interface methods● Enhanced target typing

new overload resolution & type inference

JDT Embraces Java 8 - © 2014 by Stephan Herrmann; EPL v1.0 #5

Evolution or Disruption

● Assumptions made in the implementation– Grammar can be made to conform to LALR(1)

– Type bindings can be compared with “==” (interned)

– Compilation happens in sequential phases● overload resolution is based on types being resolved● flow analysis starts after resolution is completed

– Indexing is word-based (parsing suffices)

– Code completion can stop parsing at cursor

None of these assumptions are valid for Java 8None of these assumptions are valid for Java 8

JDT Embraces Java 8 - © 2014 by Stephan Herrmann; EPL v1.0 #6

Revolution

● Fundamental changes in many places● Full rewrite of

– Type Inference

JDT Embraces Java 8 - © 2014 by Stephan Herrmann; EPL v1.0 #8

Demo: λ

JDT Embraces Java 8 - © 2014 by Stephan Herrmann; EPL v1.0 #9

● DEMO JDT Support for Lambda– Quick assist

● to / from lambda● expression block↔

– Hover ● to see the functional type● to see inference results

● Not shown– Search / Type hierarchy / Refactoring

● are lambda aware

JDT Embraces Java 8 - © 2014 by Stephan Herrmann; EPL v1.0 #10

The Compiler

● Reasons for having our own compiler– incremental compilation (as you type)

● good error recovery

– run even code with errors

– use compiler information in the UI● visualization● navigation● quick assist & refactoring

– QUALITY ASSURANCE

JDT Embraces Java 8 - © 2014 by Stephan Herrmann; EPL v1.0 #11

spec

abstractly capturethe concepts

ecj

implement the spec,the full spec,and nothing but the spec

deviation

bug?

bug?

bug?

compare behavior

javac

Java Quality Assurance

JDT Embraces Java 8 - © 2014 by Stephan Herrmann; EPL v1.0 #12

Demo: @

JDT Embraces Java 8 - © 2014 by Stephan Herrmann; EPL v1.0 #13

Areas Covered

● Connecting objects to a system– nothing new–

● Algorithms– lambda expressions

– library updates for lambdas

● Types– type annotations

– type inference

NPE

λ

JDT Embraces Java 8 - © 2014 by Stephan Herrmann; EPL v1.0 #14

Object Composition

● Properties– Dynamism:

roles can come and go(same base object)

– Multiplicities:one base can play several roles(different/same role types)

playedBy Relationship

Personname

Employeesalary

«playedBy»

joe: Personname=”joe”

:Studentmatr=0815

«base»

:Employeesalary=100

«base»

:Employeesalary=2000

«bas

e»

Employeesalary

Role Base

Personname

JDT Embraces Java 8 - © 2014 by Stephan Herrmann; EPL v1.0 #15

Areas Covered

● Connecting objects to a system– Object Teams–

● Algorithms– lambda expressions

– library updates for lambdas

● Types– type annotations

– type inference

NPE

λ Java 8 ready