| <?php |
| /******************************************************************************* |
| * Copyright (c) 2015 Eclipse Foundation and others. |
| * All rights reserved. This program and the accompanying materials |
| * are made available under the terms of the Eclipse Public License v1.0 |
| * which accompanies this distribution, and is available at |
| * http://eclipse.org/legal/epl-v10.html |
| * |
| * Contributors: |
| * Eric Poirier (Eclipse Foundation) - Initial implementation |
| *******************************************************************************/ |
| ?> |
| |
| <h1 class="article-title"><?php echo $pageTitle; ?></h1> |
| <p> |
| <a target="_blank" href="http://docs.oracle.com/javase/8/">Java SE 8</a> |
| is the most significant expansion of the Java programming model yet |
| and <a target="_blank" href="https://www.eclipse.org/luna/">Eclipse |
| Luna (R 4.4)</a> has been reloaded to be ready for Java 8. |
| </p> |
| <p>Here is a glimpse of goodies provided by Eclipse as part of the |
| Java 8 support:</p> |
| |
| <p> |
| <a |
| href="/community/eclipse_newsletter/2014/june/images/article1.1.png"><img |
| class="img-responsive" |
| src="/community/eclipse_newsletter/2014/june/images/article1.1.png" alt="" /></a> |
| </p> |
| <br /> |
| <h1> |
| Under the hood |
| </h1> |
| <p>The Java tooling in Eclipse has its own compiler implementation |
| which not only generates the class files, but also produces a Java |
| document model which forms the basis for implementing a large number |
| of tooling features.</p> |
| <p>Preparing Eclipse to be Java 8 ready involved a series of steps |
| filled with technical and process challenges to support all the |
| incremental updates of the Java Language Specification: the parser, |
| compiler and indexer were evolved, the new type inference engine was |
| developed, debugger evaluation support was added, major updates were |
| introduced in DOM AST and Java model APIs, existing functionality |
| was retooled to blend with the new language features and new |
| functionality was added to make your experience with Java 8 more |
| pleasant.</p> |
| |
| <h1> |
| Highlights |
| </h1> |
| <ul> |
| <li>The Eclipse Compiler for Java (ECJ) implements all the new Java |
| 8 language enhancements.<br /> <a |
| href="/community/eclipse_newsletter/2014/june/images/article1.2.png"><img |
| width="600" |
| src="/community/eclipse_newsletter/2014/june/images/article1.2.png" alt="" /></a> |
| </li> |
| <li>Quickly change a project to be compatible with Java 8:<br /> <a |
| href="/community/eclipse_newsletter/2014/june/images/article1.3.png"><img |
| width="600" |
| src="/community/eclipse_newsletter/2014/june/images/article1.3.png" alt="" /></a></li> |
| <li>Convert anonymous class creations to lambda expressions (and |
| back) by invoking the <b>Quick Assists (Ctrl+1)</b>: |
| <ul> |
| <li>Convert to lambda expression</li> |
| <li>Convert to anonymous class creation</li> |
| </ul> <a |
| href="/community/eclipse_newsletter/2014/june/images/article1.4.png"><img |
| width="600" |
| src="/community/eclipse_newsletter/2014/june/images/article1.4.png" alt="" /></a> |
| </li> |
| <li> Or invoke |
| <b>Source > Clean Up...</b> to migrate all your existing code to use |
| lambda expressions where applicable: |
| <br /> |
| |
| <a |
| href="/community/eclipse_newsletter/2014/june/images/article1.5.png"><img |
| width="600" |
| src="/community/eclipse_newsletter/2014/june/images/article1.5.png" alt="" /></a> |
| <br /> |
| <br /> The functionality to migrate anonymous classes to lambda |
| expressions has been made intelligent to make sure that only valid |
| code is generated. It ignores the conversion where it is not |
| possible, and it even updates the variable names to prevent name |
| conflicts with variables from an enclosing scope. For example, the |
| conversion is not performed if the anonymous class does not |
| implement a functional interface, implements a functional interface |
| with a generic abstract method, contains additional members, |
| contains unqualified ‘this’ or ‘super’ references etc. |
| </li> |
| <li>Change lambda expression’s body to block or expression by |
| invoking the Quick Assists (Ctrl+1): |
| <ul> |
| <li>Change body expression to block <a |
| href="/community/eclipse_newsletter/2014/june/images/article1.6.png"><img |
| width="600" |
| src="/community/eclipse_newsletter/2014/june/images/article1.6.png" alt="" /></a></li> |
| <li>Change body block to expression <a |
| href="/community/eclipse_newsletter/2014/june/images/article1.7.png"><img |
| width="600" |
| src="/community/eclipse_newsletter/2014/june/images/article1.7.png" alt="" /></a></li> |
| </ul></li> |
| <li>The new concise syntax of lambda expressions and method |
| references looks nice, but it may not be so intuitive for |
| developers due to inferred target types, inferred parameter types, |
| various shorthand syntaxes for method and constructor references |
| etc. This is where Eclipse helps you to become more productive |
| while writing or understanding programs with Java 8 constructs. |
| <ul> |
| <li>To <b>view</b> the method implemented by the functional |
| interface instances, just <b>hover</b> on: |
| |
| <ul> |
| <li>‘->’ in a lambda expression<br /> <a |
| href="/community/eclipse_newsletter/2014/june/images/article1.8.png"><img |
| width="600" |
| src="/community/eclipse_newsletter/2014/june/images/article1.8.png" alt="" /></a></li> |
| <li>‘::’ in a method reference<br /> <a |
| href="/community/eclipse_newsletter/2014/june/images/article1.9.png"><img |
| width="600" |
| src="/community/eclipse_newsletter/2014/june/images/article1.9.png" alt="" /></a></li> |
| </ul></li> |
| <li>To <b>navigate</b> to the functional method declaration, hold |
| <b>Ctrl</b>, move the mouse pointer over '->' or '::', and click |
| the hyperlink: |
| <ul> |
| <li>In a lambda expression:<br /> <a |
| href="/community/eclipse_newsletter/2014/june/images/article1.10.png"><img |
| src="/community/eclipse_newsletter/2014/june/images/article1.10.png" alt="" /></a></li> |
| <li>‘::’ in a method reference<br /> <a |
| href="/community/eclipse_newsletter/2014/june/images/article1.11.png"><img |
| src="/community/eclipse_newsletter/2014/june/images/article1.11.png" alt="" /></a></li> |
| </ul> |
| |
| </ul></li> |
| <li>You can control the formatting of lambda expressions via new <b>Formatter</b> |
| options: |
| |
| <ul> |
| <li>Configure the position of <b>braces</b> in lambda body<br /> <a |
| href="/community/eclipse_newsletter/2014/june/images/article1.12.png"><img |
| src="/community/eclipse_newsletter/2014/june/images/article1.12.png" alt="" /></a></li> |
| <li>Configure the <b>whitespace</b> before and after the arrow |
| operator<br /> <a |
| href="/community/eclipse_newsletter/2014/june/images/article1.13.png"><img |
| src="/community/eclipse_newsletter/2014/june/images/article1.13.png" alt="" /></a></li> |
| </ul></li> |
| <li>You can search for method reference expressions in <b>Java |
| Search</b> by limiting the match location of methods or |
| constructors to method references:<br /> <a |
| href="/community/eclipse_newsletter/2014/june/images/article1.14.png"><img |
| width="450" |
| src="/community/eclipse_newsletter/2014/june/images/article1.14.png" alt="" /></a></li> |
| <li>The <b>Type Hierarchy</b> view and <b>Quick Hierarchy (Ctrl+T)</b> |
| (on the functional interface and its abstract method) show lambda |
| expressions also as implementations of the functional interface:<br /> |
| <a |
| href="/community/eclipse_newsletter/2014/june/images/article1.15.png"><img |
| src="/community/eclipse_newsletter/2014/june/images/article1.15.png" alt="" /></a></li> |
| <li>Eclipse also provides <b>Content Assist (Ctrl+Space)</b> support |
| for method references:<br /> <a |
| href="/community/eclipse_newsletter/2014/june/images/article1.16.png"><img |
| width="600" |
| src="/community/eclipse_newsletter/2014/june/images/article1.16.png" alt="" /></a></li> |
| <li>Quickly identify the abstract (A), default (D) and static (S) |
| methods of an interface in views like Outline, Search, Type |
| Hierarchy, Quick Outline / Hierarchy with the new icon <b>adornments</b>:<br /> |
| <a |
| href="/community/eclipse_newsletter/2014/june/images/article1.17.png"><img |
| width="600" |
| src="/community/eclipse_newsletter/2014/june/images/article1.17.png" alt="" /></a> |
| </li> |
| <li>The <b>Java debugger</b> supports breakpoints in lambda |
| expressions and evaluation or inspection in the context of |
| interface methods:<br /> <a |
| href="/community/eclipse_newsletter/2014/june/images/article1.18.png"><img |
| src="/community/eclipse_newsletter/2014/june/images/article1.18.png" alt="" /></a></li> |
| <li><b>JEP 118</b> provides the option to store information about |
| method parameters in class files when a programmer opts for it. |
| This information is then usable via reflection. In 1.8 compliance |
| mode, you can enable this with the new preference option:<br /> <a |
| href="/community/eclipse_newsletter/2014/june/images/article1.19.png"><img |
| width="450" |
| src="/community/eclipse_newsletter/2014/june/images/article1.19.png" alt="" /></a></li> |
| <li>Java tooling features like Refactorings, Source actions, Content |
| assist (Ctrl+Space), Mark occurrences, Expand selection, |
| Reconciler, Annotation Processor support etc. have been updated to |
| work well with the new Java 8 features. Here is an example of the |
| extract method support:</li> |
| <li><a |
| href="/community/eclipse_newsletter/2014/june/images/article1.20.png"><img |
| width="600" |
| src="/community/eclipse_newsletter/2014/june/images/article1.20.png" alt="" /></a> |
| </li> |
| <li><b>JSR 308</b> introduces <b>Type Annotations</b> in Java 8, and |
| Eclipse provides the support for <a target="_blank" |
| href="http://help.eclipse.org/luna/topic/org.eclipse.jdt.doc.user/tasks/task-using_null_type_annotations.htm">type |
| annotations based static null analysis</a> by shipping a set of |
| nullness annotations as version 2.0.0 of the |
| org.eclipse.jdt.annotation bundle. With these annotations, compile |
| time type checking is possible to ensure that the specified null |
| constraints are not violated and all possible |
| NullPointerExceptions are reported (active if annotation-based |
| null analysis is enabled in Java Compiler > Errors/Warnings |
| preferences): <a |
| href="/community/eclipse_newsletter/2014/june/images/article1.21.png"><img |
| width="600" |
| src="/community/eclipse_newsletter/2014/june/images/article1.21.png" alt="" /></a><br /> |
| <br />This supports API designers to create better interfaces with |
| stricter rules about what can be passed to and returned from an |
| API:<br /> <a |
| href="/community/eclipse_newsletter/2014/june/images/article1.22.png"><img |
| width="600" |
| src="/community/eclipse_newsletter/2014/june/images/article1.22.png" alt="" /></a></li> |
| <li>The Eclipse Compiler for Java (with its new Java 8 type |
| inference engine) has also been verified to successfully build |
| major projects like JRE8, OpenJFX and Eclipse SDK (~250 projects).</li> |
| </ul> |
| |
| |
| <div class="bottomitem"> |
| <h3>About the Authors</h3> |
| |
| <div class="row"> |
| <div class="col-sm-12"> |
| <div class="row"> |
| <div class="col-sm-8"> |
| <img class="author-picture" |
| src="/community/eclipse_newsletter/2014/june/images/Noopur.jpg" |
| width="75" alt="noopur gupta" /> |
| </div> |
| <div class="col-sm-16"> |
| <p class="author-name"> |
| Noopur Gupta <br /> |
| <a href="http://www.ibm.com/">IBM</a> |
| </p> |
| <ul class="author-link"> |
| <li><a href="http://about.me/noopur2507">About the author</a></li> |
| <!--<li><a href="https://twitter.com/noopur2507">Twitter</a></li> |
| $og--> |
| </ul> |
| </div> |
| </div> |
| </div> |
| </div> |
| </div> |
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