blocks|key|2961481|text|在IntelliJ+IDEA中：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2961482|在File+Menu+Project+Structure+Project→中，将Project+Language+Level更改为8.0+-+Lambdas,+type+annotations+etc.|offset|length|style|CODE|2961483|对于安卓3.0%2B+Go+File+Project+Structure+Module和app→→，在属性选项卡中将Source+Compatibility和Target+Compatibility设置为1.8+(Java+8)|2961484|截图：|2961485|​|2961486|📷|atomic|2961487|2961488|entityMap|0|IMAGE|mutability|IMMUTABLE|imageUrl|https://ask.qcloudimg.com/http-save/yehe-900000/7fc3c13ee88a027361b0642808ddfeb3.png|imageAlt^0|0|1|9|B|H|T|7|14|M|1T|10|0|C|4|H|H|Z|6|16|3|1K|K|25|K|2S|C|0|0|0|0|1|0|0|0^^$0|@$1|2|3|4|5|6|7|10|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|11|8|@$D|12|E|13|F|G]|$D|14|E|15|F|G]|$D|16|E|17|F|G]|$D|18|E|19|F|G]|$D|1A|E|1B|F|G]]|9|@]|A|$]]|$1|H|3|I|5|6|7|1C|8|@$D|1D|E|1E|F|G]|$D|1F|E|1G|F|G]|$D|1H|E|1I|F|G]|$D|1J|E|1K|F|G]|$D|1L|E|1M|F|G]|$D|1N|E|1O|F|G]|$D|1P|E|1Q|F|G]]|9|@]|A|$]]|$1|J|3|K|5|6|7|1R|8|@]|9|@]|A|$]]|$1|L|3|M|5|6|7|1S|8|@]|9|@]|A|$]]|$1|N|3|O|5|P|7|1T|8|@]|9|@$D|1U|E|1V|1|1W]]|A|$]]|$1|Q|3|M|5|6|7|1X|8|@]|9|@]|A|$]]|$1|R|3|-4|5|6|7|1Y|8|@]|9|@]|A|$]]]|S|$T|$5|U|V|W|A|$X|Y|Z|-4]]]]

In IntelliJ IDEA:

In <code>File Menu</code> → <code>Project Structure</code> → <code>Project</code>, change <code>Project Language Level</code> to <code>8.0 - Lambdas, type annotations etc.</code>

For Android 3.0+ Go <code>File</code> → <code>Project Structure</code> → <code>Module</code> → <code>app</code> and In Properties Tab set <code>Source Compatibility</code> and <code>Target Compatibility</code> to <code>1.8 (Java 8)</code>

Screenshot:

<a href="https://i.stack.imgur.com/PRjlJ.png" rel="noreferrer"><img src="https://i.stack.imgur.com/PRjlJ.png" alt="enter image description here"></a>

blocks|key|161045|text|您还应该在source选项卡(Modules+part)上更改源代码语言级别。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|161046|​|161047|📷|atomic|offset|length|161048|161049|entityMap|0|IMAGE|mutability|IMMUTABLE|imageUrl|https://ask.qcloudimg.com/http-save/yehe-900000/f255b061c23dff09d4feff8f61dae2a2.png|imageAlt^0|0|0|0|1|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|T|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|U|8|@]|9|@$G|V|H|W|1|X]]|A|$]]|$1|I|3|C|5|6|7|Y|8|@]|9|@]|A|$]]|$1|J|3|-4|5|6|7|Z|8|@]|9|@]|A|$]]]|K|$L|$5|M|N|O|A|$P|Q|R|-4]]]]

You should change source code Language Level also on the Source tab (Modules part). 

<a href="https://i.stack.imgur.com/sE2kA.png" rel="noreferrer"><img src="https://i.stack.imgur.com/sE2kA.png" alt="Change Language Level"></a>

blocks|key|157516|text|此解决方案适用于Android+Studio+3.0或更高版本。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|157517|157518|文件>项目结构>模块>应用程序>属性选项卡|ordered-list-item|157519|157520|​|157521|📷|atomic|offset|length|157522|157523|将Source+Compatibility和Target+Compatibility都更改为1.8|style|CODE|157524|157525|编辑配置文件|157526|157527|也可以直接在相应的build.gradle文件中对其进行配置|157528|android+{
++...
++//+Configure+only+for+each+module+that+uses+Java+8
++//+language+features+(either+in+its+source+code+or
++//+through+dependencies).
++compileOptions+{
++++sourceCompatibility+JavaVersion.VERSION_1_8
++++targetCompatibility+JavaVersion.VERSION_1_8
++}
}|code-block|syntax|javascript|157529|entityMap|0|IMAGE|mutability|IMMUTABLE|imageUrl|https://ask.qcloudimg.com/http-save/yehe-900000/2f9c9df49d01ab2fa2974d41b9984ca8.png|imageAlt^0|0|0|0|0|0|0|1|0|0|0|1|K|M|K|1A|3|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|1C|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|1D|8|@]|9|@]|A|$]]|$1|C|3|D|5|E|7|1E|8|@]|9|@]|A|$]]|$1|F|3|-4|5|6|7|1F|8|@]|9|@]|A|$]]|$1|G|3|H|5|6|7|1G|8|@]|9|@]|A|$]]|$1|I|3|J|5|K|7|1H|8|@]|9|@$L|1I|M|1J|1|1K]]|A|$]]|$1|N|3|H|5|6|7|1L|8|@]|9|@]|A|$]]|$1|O|3|P|5|6|7|1M|8|@$L|1N|M|1O|Q|R]|$L|1P|M|1Q|Q|R]|$L|1R|M|1S|Q|R]]|9|@]|A|$]]|$1|S|3|-4|5|6|7|1T|8|@]|9|@]|A|$]]|$1|T|3|U|5|E|7|1U|8|@]|9|@]|A|$]]|$1|V|3|-4|5|6|7|1V|8|@]|9|@]|A|$]]|$1|W|3|X|5|6|7|1W|8|@]|9|@]|A|$]]|$1|Y|3|Z|5|10|7|1X|8|@]|9|@]|A|$11|12]]|$1|13|3|-4|5|6|7|1Y|8|@]|9|@]|A|$]]]|14|$15|$5|16|17|18|A|$19|1A|1B|-4]]]]

This solution works in Android Studio 3.0 or later.

<ol>
<li>File > Project Structure > Modules > app > Properties tab</li>
</ol>

<a href="https://i.stack.imgur.com/VTKN7.png" rel="noreferrer"><img src="https://i.stack.imgur.com/VTKN7.png" alt="enter image description here"></a>

Change both of <code>Source Compatibility</code> and <code>Target Compatibility</code> to <code>1.8</code>

<ol start="2">
<li>Edit config file</li>
</ol>

You can also configure it directly in the corresponding build.gradle file

<pre><code>android {
 ...
 // Configure only for each module that uses Java 8
 // language features (either in its source code or
 // through dependencies).
 compileOptions {
 sourceCompatibility JavaVersion.VERSION_1_8
 targetCompatibility JavaVersion.VERSION_1_8
 }
}
</code></pre>

blocks|key|2961587|text|对于IntelliJ13，只需通过以下导航将项目语言级别本身更改为8.0。|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|CODE|entityRanges|data|2961588|File
%7C
%7C
+---------Project+Structure+->+Project+tab
++++++++++%7C
++++++++++%7C________Project+language+level|code-block|syntax|javascript|2961589|​|2961590|📷|atomic|2961591|2961592|模块语言级别|2961593|当没有java+compiler的maven插件时，我也不得不更新Modules+lang+level。|2961594|File
%7C
%7C
+---------Project+Structure+->+Modules+tab
++++++++++%7C
++++++++++%7C________+language+level|2961595|2961596|2961597|2961598|但是如果已经有了一个Module+lang+level，这个maven+plugin就会自动修复，|2961599|++++<plugin>
++++++++<groupId>org.apache.maven.plugins</groupId>
++++++++<artifactId>maven-compiler-plugin</artifactId>
++++++++<version>3.6.0</version>
++++++++<configuration>
++++++++++++<source>1.8</source>
++++++++++++<target>1.8</target>
++++++++</configuration>
++++</plugin>|2961600|更改后的一切看起来都很好|2961601|entityMap|0|IMAGE|mutability|IMMUTABLE|imageUrl|https://ask.qcloudimg.com/http-save/yehe-900000/9b6626c65834a6fd2cfdb29b67d30a1d.png|imageAlt|1|https://ask.qcloudimg.com/http-save/yehe-900000/050a1b04fe857782fb6ca2a09af0b87d.png^0|M|6|X|3|0|0|0|0|1|0|0|0|0|3|D|X|I|0|0|0|0|1|1|0|0|A|H|U|C|0|0|4|8|0^^$0|@$1|2|3|4|5|6|7|1H|8|@$9|1I|A|1J|B|C]|$9|1K|A|1L|B|D]]|E|@]|F|$]]|$1|G|3|H|5|I|7|1M|8|@]|E|@]|F|$J|K]]|$1|L|3|M|5|6|7|1N|8|@]|E|@]|F|$]]|$1|N|3|O|5|P|7|1O|8|@]|E|@$9|1P|A|1Q|1|1R]]|F|$]]|$1|Q|3|M|5|6|7|1S|8|@]|E|@]|F|$]]|$1|R|3|S|5|6|7|1T|8|@]|E|@]|F|$]]|$1|T|3|U|5|6|7|1U|8|@$9|1V|A|1W|B|D]|$9|1X|A|1Y|B|D]]|E|@]|F|$]]|$1|V|3|W|5|I|7|1Z|8|@]|E|@]|F|$J|K]]|$1|X|3|M|5|6|7|20|8|@]|E|@]|F|$]]|$1|Y|3|O|5|P|7|21|8|@]|E|@$9|22|A|23|1|24]]|F|$]]|$1|Z|3|M|5|6|7|25|8|@]|E|@]|F|$]]|$1|10|3|11|5|6|7|26|8|@$9|27|A|28|B|D]|$9|29|A|2A|B|D]]|E|@]|F|$]]|$1|12|3|13|5|I|7|2B|8|@]|E|@]|F|$J|K]]|$1|14|3|15|5|6|7|2C|8|@$9|2D|A|2E|B|C]]|E|@]|F|$]]|$1|16|3|-4|5|6|7|2F|8|@]|E|@]|F|$]]]|17|$18|$5|19|1A|1B|F|$1C|1D|1E|-4]]|1F|$5|19|1A|1B|F|$1C|1G|1E|-4]]]]

For intellij 13, 
Simply change the Project language level itself to <code>8.0</code> with following navigation. 

<pre><code>File
|
|
 ---------Project Structure -&gt; Project tab
 |
 |________Project language level
</code></pre>

<img src="https://i.stack.imgur.com/Cg5hw.png" alt="java8">

<h2>Module lang level</h2>

I also had to update <code>Modules lang level</code> when there was no maven plugin for <code>java compiler</code>.

<pre><code>File
|
|
 ---------Project Structure -&gt; Modules tab
 |
 |________ language level
</code></pre>

<a href="https://i.stack.imgur.com/paa1L.png" rel="noreferrer"><img src="https://i.stack.imgur.com/paa1L.png" alt="Modules lang level"></a>

But this <code>Module lang level</code> would automatically be fixed if there's already a <code>maven plugin</code> for it, 

<pre><code> &lt;plugin&gt;
 &lt;groupId&gt;org.apache.maven.plugins&lt;/groupId&gt;
 &lt;artifactId&gt;maven-compiler-plugin&lt;/artifactId&gt;
 &lt;version&gt;3.6.0&lt;/version&gt;
 &lt;configuration&gt;
 &lt;source&gt;1.8&lt;/source&gt;
 &lt;target&gt;1.8&lt;/target&gt;
 &lt;/configuration&gt;
 &lt;/plugin&gt;
</code></pre>

After changes everything looks good

blocks|key|158722|text|在Android+studio+canary+build(3.%2B)中，您可以执行以下操作：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|158723|文件->项目结构->查看模块部分，有您的类的模块的名称。单击要在其中将java升级到1.8版本的模块。->将“源兼容性”和“目标兼容性”从1.7或更低更改为1.8。不要更改其他任何内容。->单击Apply|offset|length|style|BOLD|158724|现在gradle将重新同步，您的错误将被删除。|158725|entityMap^0|0|0|2U|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|M|8|@$D|N|E|O|F|G]]|9|@]|A|$]]|$1|H|3|I|5|6|7|P|8|@]|9|@]|A|$]]|$1|J|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|K|$]]

In Android studio canary build(3.+), you can do the following:

File -> Project Structure -> Look in Modules Section, there are names of modules of your class. Click on the module in which you want to upgrade java to 1.8 version. -> Change "Source Compatibility" and "Target Compatibility" to 1.8 from 1.7 or lower. Do not change anything else. -> Click Apply

now gradle will re-sync and your error will be removed.

blocks|key|2961896|text|只需在build.gradle+yours应用程序中添加compileOptions：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|2961897|android+{


...

++defaultConfig+{
++++...
++++jackOptions+{
++++++enabled+true
++++}
++}
++compileOptions+{
++++sourceCompatibility+JavaVersion.VERSION_1_8
++++targetCompatibility+JavaVersion.VERSION_1_8
++}
}|code-block|syntax|javascript|2961898|entityMap^0|S|E|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|P|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|L|$]]

Just add <code>compileOptions</code> in build.gradle yours app:

<pre><code>android {


...

 defaultConfig {
 ...
 jackOptions {
 enabled true
 }
 }
 compileOptions {
 sourceCompatibility JavaVersion.VERSION_1_8
 targetCompatibility JavaVersion.VERSION_1_8
 }
}
</code></pre>

blocks|key|2961935|text|适用于最新使用Android+studio+3.0.1或以上版本的用户。只需单击Alt+%2B+Enter并将您的语言级别升级到8.0+-+Lambdas、类型注释等。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2961936|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

For latest users using Android studio 3.0.1 or above. Simply click Alt + Enter and upgrade your language level to 8.0 - Lambdas, type annotations etc.

blocks|key|157565|text|如果您在语言5中不受支持，请检查以下内容：(对于我来说，它位于模块部分)|type|unstyled|depth|inlineStyleRanges|entityRanges|data|157566|​|157567|📷|atomic|offset|length|157568|157569|entityMap|0|IMAGE|mutability|IMMUTABLE|imageUrl|https://ask.qcloudimg.com/http-save/yehe-900000/7a6d0a411cede73a112c9268a7e63840.png|imageAlt^0|0|0|0|1|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|T|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|U|8|@]|9|@$G|V|H|W|1|X]]|A|$]]|$1|I|3|C|5|6|7|Y|8|@]|9|@]|A|$]]|$1|J|3|-4|5|6|7|Z|8|@]|9|@]|A|$]]]|K|$L|$5|M|N|O|A|$P|Q|R|-4]]]]

If you are getting Not supported at Language 5, check this: (
For me it was in the Modules section)

<a href="https://i.stack.imgur.com/OMkUs.png" rel="noreferrer"><img src="https://i.stack.imgur.com/OMkUs.png" alt="Lanaguge Level 5 not supported"></a>

blocks|key|161273|text|7.0不支持lambda表达式。只需将此代码添加到您的应用gradle中，即可将您的语言级别更改为8.0：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|161274|compileOptions+{
++++targetCompatibility+1.8
++++sourceCompatibility+1.8
}|code-block|syntax|javascript|161275|​|161276|📷|atomic|offset|length|161277|161278|entityMap|0|IMAGE|mutability|IMMUTABLE|imageUrl|https://ask.qcloudimg.com/http-save/yehe-900000/038cdfb91cc52b1c188565362928204f.png|imageAlt^0|0|0|0|0|1|0|0|0^^$0|@$1|2|3|4|5|6|7|X|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|Y|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Z|8|@]|9|@]|A|$]]|$1|I|3|J|5|K|7|10|8|@]|9|@$L|11|M|12|1|13]]|A|$]]|$1|N|3|H|5|6|7|14|8|@]|9|@]|A|$]]|$1|O|3|-4|5|6|7|15|8|@]|9|@]|A|$]]]|P|$Q|$5|R|S|T|A|$U|V|W|-4]]]]

7.0 does not support lambda expressions. Just add this to your app gradle to change your language level to 8.0:

<pre><code>compileOptions {
 targetCompatibility 1.8
 sourceCompatibility 1.8
}
</code></pre>

<a href="https://i.stack.imgur.com/CD2Ap.png" rel="noreferrer"><img src="https://i.stack.imgur.com/CD2Ap.png" alt="enter image description here"></a>

blocks|key|159671|text|实际上，Eclipse对Java8的支持是可用的:参见here和here。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|159672|159673|For+Kepler，它是针对SR2+(即Eclipse4.3.2)和|unordered-list-item|159674|(Eclipse4.4)的“功能补丁”，它将在标准版本中提供。(release+schedule)|159675|159676|entityMap|0|LINK|mutability|MUTABLE|url|https://wiki.eclipse.org/JDT_Core/Java8#Installation_instructions|1|http://waynebeaton.wordpress.com/2014/03/18/official-eclipse-support-for-java-8/|2|http://wiki.eclipse.org/Luna/Simultaneous_Release_Plan#Schedule^0|R|4|0|W|4|1|0|0|0|W|G|2|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@$A|X|B|Y|1|Z]|$A|10|B|11|1|12]]|C|$]]|$1|D|3|-4|5|6|7|13|8|@]|9|@]|C|$]]|$1|E|3|F|5|G|7|14|8|@]|9|@]|C|$]]|$1|H|3|I|5|G|7|15|8|@]|9|@$A|16|B|17|1|18]]|C|$]]|$1|J|3|-4|5|6|7|19|8|@]|9|@]|C|$]]|$1|K|3|-4|5|6|7|1A|8|@]|9|@]|C|$]]]|L|$M|$5|N|O|P|C|$Q|R]]|S|$5|N|O|P|C|$Q|T]]|U|$5|N|O|P|C|$Q|V]]]]

Actually, Eclipse support for Java 8 is available: see <a href="https://wiki.eclipse.org/JDT_Core/Java8#Installation_instructions" rel="nofollow">here</a> and <a href="http://waynebeaton.wordpress.com/2014/03/18/official-eclipse-support-for-java-8/" rel="nofollow">here</a>.

<ul>
<li>For Kepler, it is available as a "feature patch" against SR2 (i.e. Eclipse 4.3.2)</li>
<li>For Luna (Eclipse 4.4) it will be in the standard release. (<a href="http://wiki.eclipse.org/Luna/Simultaneous_Release_Plan#Schedule" rel="nofollow">release schedule</a>)</li>
</ul>

blocks|key|159789|text|在IntelliJ+IDEA+15中用Java8+(lambdas等)编译；|type|unstyled|depth|inlineStyleRanges|entityRanges|data|159790|159791|CTRL+%2B+ALT+%2B+SHIFT+%2B+S或文件/项目结构|unordered-list-item|offset|length|style|CODE|159792|打开项目选项卡|159793|将项目开发工具包设置为兼容java版本(1.8)|159794|将项目语言级别设置为8+Java+Compiler|159795|Change打开模块选项卡|159796|<代码>H112将语言级别设置为8，然后单击确定Java或文件/Java执行、部署/编译器/Java+Java目标字节码版本为1.8，然后单击确定<代码>H220<代码>F221|159797|entityMap^0|0|0|0|M|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|V|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|W|8|@]|9|@]|A|$]]|$1|C|3|D|5|E|7|X|8|@$F|Y|G|Z|H|I]]|9|@]|A|$]]|$1|J|3|K|5|E|7|10|8|@]|9|@]|A|$]]|$1|L|3|M|5|E|7|11|8|@]|9|@]|A|$]]|$1|N|3|O|5|E|7|12|8|@]|9|@]|A|$]]|$1|P|3|Q|5|E|7|13|8|@]|9|@]|A|$]]|$1|R|3|S|5|6|7|14|8|@]|9|@]|A|$]]|$1|T|3|-4|5|6|7|15|8|@]|9|@]|A|$]]]|U|$]]

To compile with Java 8 (lambdas etc) in IntelliJ IDEA 15;

<ul>
<li><code>CTRL + ALT + SHIFT + S</code> or File / Project Structure</li>
<li>Open Project tab</li>
<li>Set Project SDK to compatible java version (1.8)</li>
<li>Set Project language level to 8 </li>
<li>Open Modules tab</li>
<li>Set Language level to 8, click OK </li>
<li><code>CTRL + ALT + S</code> or File / Settings</li>
<li>Build, Execution, Deployment / Compiler / Java Compiler</li>
<li>Change Target bytecode version to 1.8, click OK</li>
</ul>

blocks|key|159698|text|正如Stephen+C所指出的，当安装补丁时，Eclipse+Kepler+(4.3)支持Java8(安装说明here)|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|159699|安装好后，你需要告诉你的项目使用java8。首先将JDK添加到eclipse：|159700|159701|转到窗口->+Preferences|unordered-list-item|159702|转到Java+->+Installed+JRE|159703|Add+Standard+VM，并指向JRE|159704|的位置，然后转到编译器|159705|<代码>H110将编译器合规性级别设置为1.8<代码>H211<代码>F212|159706|然后告诉项目使用JDK+1.8：|159707|159708|转到项目Compiler|159709|Enable+preferences|159710|Go+to+|159711|项目特定设置|159712|将编译器合规性级别设置为1.8|159713|159714|159715|entityMap|0|LINK|mutability|MUTABLE|url|https://wiki.eclipse.org/JDT/Eclipse_Java_8_Support_For_Kepler^0|1J|4|0|0|0|0|0|0|0|0|0|0|0|0|0|1|1|1|0|0^^$0|@$1|2|3|4|5|6|7|1E|8|@]|9|@$A|1F|B|1G|1|1H]]|C|$]]|$1|D|3|E|5|6|7|1I|8|@]|9|@]|C|$]]|$1|F|3|-4|5|6|7|1J|8|@]|9|@]|C|$]]|$1|G|3|H|5|I|7|1K|8|@]|9|@]|C|$]]|$1|J|3|K|5|I|7|1L|8|@]|9|@]|C|$]]|$1|L|3|M|5|I|7|1M|8|@]|9|@]|C|$]]|$1|N|3|O|5|I|7|1N|8|@]|9|@]|C|$]]|$1|P|3|Q|5|6|7|1O|8|@]|9|@]|C|$]]|$1|R|3|S|5|6|7|1P|8|@]|9|@]|C|$]]|$1|T|3|-4|5|6|7|1Q|8|@]|9|@]|C|$]]|$1|U|3|V|5|I|7|1R|8|@]|9|@]|C|$]]|$1|W|3|X|5|I|7|1S|8|@]|9|@]|C|$]]|$1|Y|3|Z|5|I|7|1T|8|@]|9|@]|C|$]]|$1|10|3|11|5|I|7|1U|8|@]|9|@]|C|$]]|$1|12|3|13|5|I|7|1V|8|@]|9|@]|C|$]]|$1|14|3|-4|5|6|7|1W|8|@]|9|@]|C|$]]|$1|15|3|-4|5|6|7|1X|8|@]|9|@]|C|$]]|$1|16|3|-4|5|6|7|1Y|8|@]|9|@]|C|$]]]|17|$18|$5|19|1A|1B|C|$1C|1D]]]]

As Stephen C pointed out, Eclipse Kepler (4.3) has Java 8 support when the patch is installed (installation instructions <a href="https://wiki.eclipse.org/JDT/Eclipse_Java_8_Support_For_Kepler" rel="nofollow">here</a>)

Once installed, you’ll need to tell your projects to use java 8. First add the JDK to eclipse:

<ul>
<li>Go to Window -> Preferences</li>
<li>Go to Java -> Installed JREs</li>
<li>Add Standard VM, and point to the location of the JRE</li>
<li>Then go to Compiler</li>
<li>Set Compiler compliance level to 1.8</li>
</ul>

Then tell the project to use JDK 1.8:

<ul>
<li>Go to Project -> preferences</li>
<li>Go to Java Compiler</li>
<li>Enable project specific settings</li>
<li>Set Compiler compliance level to 1.8</li>
</ul>

blocks|key|161241|text|检查以下设置：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|161242|161243|文件->项目结构->项目页签。|ordered-list-item|161244|161245|*工程SDK设置为8或above.*|161246|File->Project+Structure->Modules。|unordered-list-item|161247|161248|*检查您或所有模块的语言级别是否设置为8或above.*|161249|File->Settings(or其他设置->较新Idea版本中新项目的首选项)|161250|161251|*搜索Java编译器并检查项目字节码版本和每个模块字节码版本是否设置为8或更高。*|161252|您的问题可能属于上面定义的任何一个类别。|161253|entityMap^0|0|0|0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|X|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|Y|8|@]|9|@]|A|$]]|$1|C|3|D|5|E|7|Z|8|@]|9|@]|A|$]]|$1|F|3|-4|5|6|7|10|8|@]|9|@]|A|$]]|$1|G|3|H|5|6|7|11|8|@]|9|@]|A|$]]|$1|I|3|J|5|K|7|12|8|@]|9|@]|A|$]]|$1|L|3|-4|5|6|7|13|8|@]|9|@]|A|$]]|$1|M|3|N|5|6|7|14|8|@]|9|@]|A|$]]|$1|O|3|P|5|K|7|15|8|@]|9|@]|A|$]]|$1|Q|3|-4|5|6|7|16|8|@]|9|@]|A|$]]|$1|R|3|S|5|6|7|17|8|@]|9|@]|A|$]]|$1|T|3|U|5|6|7|18|8|@]|9|@]|A|$]]|$1|V|3|-4|5|6|7|19|8|@]|9|@]|A|$]]]|W|$]]

Check below settings:

<ol>
<li>File->Project Structure->Project Tab. 

<pre><code>*Project SDK should be set to 8 or above.*
</code></pre></li>
<li>File->Project Structure->Modules.

<pre><code>*Check that your or all modules has Language level set to 8 or above.*
</code></pre></li>
<li>File->Settings(or Other Settings->Preference for new projects in newer Idea version)

<pre><code>*Search for Java compiler and check if Project byte code version 
and per module byte code version is set 8 or above.*
</code></pre></li>
</ol>

You problem may fall into any one of the category defined above.

blocks|key|160074|text|相同的项目(Android+Studio+3.3.2，gradle-4.10.1-all.zip，compileSdkVersion+28，buildToolsVersion+'28.0.3')在新的快速视窗机上运行良好，并在旧的Ubuntu18.04笔记本电脑上用红色下划线Java+8+stuff+(然而该项目在Ubuntu上编译没有错误)。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|BOLD|entityRanges|data|160075|我只更改了两件事来强制它停止使用红色下划线，那就是排除了incremental+true和dexOptions|160076|compileOptions+{
//++++incremental+true
++++sourceCompatibility+JavaVersion.VERSION_1_8
++++targetCompatibility+JavaVersion.VERSION_1_8
}

//dexOptions+{
//++++javaMaxHeapSize+"4g"
//}|code-block|syntax|javascript|160077|在app级别的build.gradle中。|160078|entityMap^0|6|K|R|L|1D|K|1Y|Q|3U|6|2Q|7|35|I|0|S|G|19|A|0|0|1|3|7|C|0^^$0|@$1|2|3|4|5|6|7|R|8|@$9|S|A|T|B|C]|$9|U|A|V|B|C]|$9|W|A|X|B|C]|$9|Y|A|Z|B|C]|$9|10|A|11|B|C]|$9|12|A|13|B|D]|$9|14|A|15|B|D]]|E|@]|F|$]]|$1|G|3|H|5|6|7|16|8|@$9|17|A|18|B|C]|$9|19|A|1A|B|C]]|E|@]|F|$]]|$1|I|3|J|5|K|7|1B|8|@]|E|@]|F|$L|M]]|$1|N|3|O|5|6|7|1C|8|@$9|1D|A|1E|B|C]|$9|1F|A|1G|B|C]]|E|@]|F|$]]|$1|P|3|-4|5|6|7|1H|8|@]|E|@]|F|$]]]|Q|$]]

The same project (<code>Android Studio 3.3.2</code>, <code>gradle-4.10.1-all.zip</code>, <code>compileSdkVersion 28</code>, <code>buildToolsVersion '28.0.3'</code>)
works fine on the new fast Windows machine and underline <code>Java 8</code> stuff by red color on the old Ubuntu 18.04 laptop (however project is compiling without errors on Ubuntu).

The only two things I have changed to force it to stop underlining by red were excluding of <code>incremental true</code> and <code>dexOptions</code>

<pre><code>compileOptions {
// incremental true
 sourceCompatibility JavaVersion.VERSION_1_8
 targetCompatibility JavaVersion.VERSION_1_8
}

//dexOptions {
// javaMaxHeapSize "4g"
//}
</code></pre>

in the <code>app</code>- level <code>build.gradle</code>.

blocks|key|161063|text|在intellij+14中，以下设置对我有效。Intellij14+Settings|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|161064|entityMap|0|LINK|mutability|MUTABLE|url|http://i.stack.imgur.com/bucbD.png^0|N|J|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

In intellij 14, following settings worked for me.
<a href="http://i.stack.imgur.com/bucbD.png" rel="nofollow">Intellij14 Settings</a>

blocks|key|2961720|text|即使在IntelliJ和Eclipse上应用了上面定义的特定于项目的设置，对我来说还是失败了！|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2961721|为我工作的是在POM：中添加了带有源和目标的maven插件，设置为1.8|offset|length|style|BOLD|2961722|<build>
++++<plugins>
++++++++<plugin>
++++++++++++<groupId>org.apache.maven.plugins</groupId>
++++++++++++<artifactId>maven-compiler-plugin</artifactId>
++++++++++++<version>2.0.2</version>
++++++++++++<configuration>
++++++++++++++++<source>1.8</source>
++++++++++++++++<target>1.8</target>
++++++++++++</configuration>
++++++++</plugin>

++++++++<plugin>
++++++++++++<groupId>org.apache.maven.plugins</groupId>
++++++++++++<artifactId>maven-jar-plugin</artifactId>
++++++++++++<configuration>
++++++++++++++++<archive>
++++++++++++++++++++<manifest>
++++++++++++++++++++++++<addClasspath>true</addClasspath>
++++++++++++++++++++++++<classpathPrefix>lib/</classpathPrefix>
++++++++++++++++++++++++<mainClass>com.abc.sparkcore.JavaWordCount</mainClass>
++++++++++++++++++++</manifest>
++++++++++++++++</archive>
++++++++++++</configuration>
++++++++</plugin>
++++++++<plugin>
++++++++++++<groupId>org.apache.maven.plugins</groupId>
++++++++++++<artifactId>maven-dependency-plugin</artifactId>
++++++++++++<executions>
++++++++++++++++<execution>
++++++++++++++++++++<id>copy</id>
++++++++++++++++++++<phase>install</phase>
++++++++++++++++++++<goals>
++++++++++++++++++++++++<goal>copy-dependencies</goal>
++++++++++++++++++++</goals>
++++++++++++++++++++<configuration>
<outputDirectory>${project.build.directory}/lib</outputDirectory>
++++++++++++++++++++</configuration>+++
+++++</execution>
++++++++++++</executions>
++++++++</plugin>
++++</plugins>
</build>+|code-block|syntax|javascript|2961723|entityMap^0|0|0|B|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|P|8|@$D|Q|E|R|F|G]]|9|@]|A|$]]|$1|H|3|I|5|J|7|S|8|@]|9|@]|A|$K|L]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

Even after applying above defined project specific settings on IntelliJ as well as Eclipse, it was still failing for me !

what worked for me was addition of maven plugin with source and target with 1.8 setting in POM XML:

<pre><code>&lt;build&gt;
 &lt;plugins&gt;
 &lt;plugin&gt;
 &lt;groupId&gt;org.apache.maven.plugins&lt;/groupId&gt;
 &lt;artifactId&gt;maven-compiler-plugin&lt;/artifactId&gt;
 &lt;version&gt;2.0.2&lt;/version&gt;
 &lt;configuration&gt;
 &lt;source&gt;1.8&lt;/source&gt;
 &lt;target&gt;1.8&lt;/target&gt;
 &lt;/configuration&gt;
 &lt;/plugin&gt;

 &lt;plugin&gt;
 &lt;groupId&gt;org.apache.maven.plugins&lt;/groupId&gt;
 &lt;artifactId&gt;maven-jar-plugin&lt;/artifactId&gt;
 &lt;configuration&gt;
 &lt;archive&gt;
 &lt;manifest&gt;
 &lt;addClasspath&gt;true&lt;/addClasspath&gt;
 &lt;classpathPrefix&gt;lib/&lt;/classpathPrefix&gt;
 &lt;mainClass&gt;com.abc.sparkcore.JavaWordCount&lt;/mainClass&gt;
 &lt;/manifest&gt;
 &lt;/archive&gt;
 &lt;/configuration&gt;
 &lt;/plugin&gt;
 &lt;plugin&gt;
 &lt;groupId&gt;org.apache.maven.plugins&lt;/groupId&gt;
 &lt;artifactId&gt;maven-dependency-plugin&lt;/artifactId&gt;
 &lt;executions&gt;
 &lt;execution&gt;
 &lt;id&gt;copy&lt;/id&gt;
 &lt;phase&gt;install&lt;/phase&gt;
 &lt;goals&gt;
 &lt;goal&gt;copy-dependencies&lt;/goal&gt;
 &lt;/goals&gt;
 &lt;configuration&gt;
&lt;outputDirectory&gt;${project.build.directory}/lib&lt;/outputDirectory&gt;
 &lt;/configuration&gt; 
 &lt;/execution&gt;
 &lt;/executions&gt;
 &lt;/plugin&gt;
 &lt;/plugins&gt;
&lt;/build&gt; 
</code></pre>

blocks|key|159867|text|可能原因#1+(与此问题的前3个答案相同)：项目结构设置|type|unstyled|depth|inlineStyleRanges|entityRanges|data|159868|159869|文件>项目结构>在项目设置下，转到项目>将项目开发工具包设置为1.8+(版本为65或更高版本，最新版本为112)，并将项目语言级别设置为8。|ordered-list-item|offset|length|style|BOLD|159870|文件>项目结构>在平台设置下，转到项目>确保JDK主路径设置为1.8+(版本为65或更高版本，最新版本为112)。H210G211|159871|159872|如果上述方法不起作用，请检查编译器的目标字节码版本，然后转到可能的原因#2。|159873|可能的原因#2:编译器|159874|Java+|159875|File>+Settings+>+Build，Execution，Deployment+>在编译器下，转到+Compiler+>将您的项目字节码版本设置为1.8，以及您的模块的所有目标字节码版本。单击Apply，然后单击OK。重新启动IntelliJ集成开发环境。此时，我的集成开发环境接受了Lambda表达式。|unordered-list-item|159876|159877|最好的祝福:)|159878|entityMap^0|0|0|L|7|1N|6|0|M|17|0|0|0|12|0|0|B|0|0|5|0|0|4C|0|0|0|7|0^^$0|@$1|2|3|4|5|6|7|10|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|11|8|@]|9|@]|A|$]]|$1|C|3|D|5|E|7|12|8|@$F|13|G|14|H|I]|$F|15|G|16|H|I]]|9|@]|A|$]]|$1|J|3|K|5|E|7|17|8|@$F|18|G|19|H|I]]|9|@]|A|$]]|$1|L|3|-4|5|6|7|1A|8|@]|9|@]|A|$]]|$1|M|3|N|5|6|7|1B|8|@$F|1C|G|1D|H|I]]|9|@]|A|$]]|$1|O|3|P|5|6|7|1E|8|@$F|1F|G|1G|H|I]]|9|@]|A|$]]|$1|Q|3|R|5|6|7|1H|8|@$F|1I|G|1J|H|I]]|9|@]|A|$]]|$1|S|3|T|5|U|7|1K|8|@$F|1L|G|1M|H|I]]|9|@]|A|$]]|$1|V|3|-4|5|6|7|1N|8|@]|9|@]|A|$]]|$1|W|3|X|5|6|7|1O|8|@$F|1P|G|1Q|H|I]]|9|@]|A|$]]|$1|Y|3|-4|5|6|7|1R|8|@]|9|@]|A|$]]]|Z|$]]

Possible Cause #1 (same as the first 3 answers for this question): Project Structure Settings

<ol>
<li>File > Project Structure > Under Project Settings, go to Project > set Project SDK to 1.8 (with version 65 or above, latest is 112) and set Project Language Level to 8.</li>
<li>File > Project Structure > Under Platform Settings, go to Project > ensure that your JDK home path is set to 1.8 (with version 65 or above, latest is 112).</li>
</ol>

If the above does not work, check the target bytecode version of your compiler and move on to Possible Cause #2.

Possible Cause #2: Compiler

<ol>
<li>File > Settings > Build, Execution, Deployment > Under Compiler, go to Java Compiler > set your Project Bytecode Version to 1.8, as well as all the Target Bytecode Version for your modules. Click Apply and hit OK. Restart your IntelliJ IDE. Lambda expression was accepted in my IDE at this point.</li>
</ol>

Best wishes :)

blocks|key|2961919|text|对我来说，提供的解决方案都不起作用。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2961920|这应该是您最后的选择：->打开项目的.iml文件，将LANGUAGE_LEVEL更改为JDK_1_8或您想要的任何版本。->如果这没有帮助，你应该在你的项目根目录中使用grep+"JDK“，找到包含版本设置的文件，并将其设置为你喜欢的版本。|2961921|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|G|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|H|8|@]|9|@]|A|$]]]|E|$]]

For me none of the solutions provided worked.

This should be your last resort:
-> Open .iml file of your project change the LANGUAGE_LEVEL to JDK_1_8 or whatever version you wish.
-> If this didn't help, you should grep "JDK" in your project root directory and find the file which contains version setting and set it to your preferred version.

blocks|key|157668|text|在安卓项目的app级build.gradle中添加以下行，解决了问题。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|157669|+compileOptions+{
++++++++sourceCompatibility+=+JavaVersion.VERSION_1_8
++++++++targetCompatibility+=+JavaVersion.VERSION_1_8
++++}|code-block|syntax|javascript|157670|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Adding below lines in app level build.gradle in Android project solved issue.
<pre><code> compileOptions {
 sourceCompatibility = JavaVersion.VERSION_1_8
 targetCompatibility = JavaVersion.VERSION_1_8
 }
</code></pre>

blocks|key|2749144|text|然后从项目中选择language+level+1.8，阅读有关Lambda+Expression+here的更多信息|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|2749145|entityMap|0|LINK|mutability|MUTABLE|url|http://www.schoolay.com/Java-8/Java-8-Lambda-Expressions.html^0|1D|4|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

Ctrl + Alt + Shift + S and then from project select the language level 1.8, read more about Lambda Expressions <a href="http://www.schoolay.com/Java-8/Java-8-Lambda-Expressions.html" rel="nofollow">here</a>

blocks|key|157554|text|要对lambda表达式支持Ecplise，请执行以下操作：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|157555|157556|确保您使用的是JDK1.8(窗口>首选项>已安装的JRE和编译器)；|ordered-list-item|157557|如果您定义了任何新的函数接口，则使用注释@FunctionalInterface，以便eclipse将建议您进行与Lambdas+(+Functional+Interfaces.)|offset|length|157558|157559|entityMap|0|LINK|mutability|MUTABLE|url|https://tutoref.com/java-8-lambda-expressions-tutorial/#functional-interfaces^0|0|0|0|1V|L|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|T|8|@]|9|@]|A|$]]|$1|C|3|D|5|E|7|U|8|@]|9|@]|A|$]]|$1|F|3|G|5|E|7|V|8|@]|9|@$H|W|I|X|1|Y]]|A|$]]|$1|J|3|-4|5|6|7|Z|8|@]|9|@]|A|$]]|$1|K|3|-4|5|6|7|10|8|@]|9|@]|A|$]]]|L|$M|$5|N|O|P|A|$Q|R]]]]

To have support of Ecplise for lambda expressions :

<ol>
<li>Make sure you are using JDK 1.8 (Window > Preferences > Installed JREs and Compiler );</li>
<li>Use the annotation @FunctionalInterface if you define any new functional interfaces so that eclipse will suggest you refactorings related to Lambdas ( <a href="https://tutoref.com/java-8-lambda-expressions-tutorial/#functional-interfaces" rel="nofollow noreferrer">Functional Interfaces</a>. )</li>
</ol>

blocks|key|161231|text|首先检查您正在使用的JDK的版本，它应该高于1.8。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|161232|如果是，则继续执行以下步骤。|161233|更改Intellij中项目和模块的语言级别。|offset|length|style|BOLD|161234|项目|161235|161236|+1.文件->项目结构->项目->项目语言级别将其更改为8以使lamba表达式起作用|blockquote|161237|161238|2.文件->项目结构->模块->项目语言级别将其更改为8，以使lamba表达式在中工作|161239|entityMap^0|0|0|2|8|0|0|2|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|V|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|W|8|@$F|X|G|Y|H|I]]|9|@]|A|$]]|$1|J|3|K|5|6|7|Z|8|@$F|10|G|11|H|I]]|9|@]|A|$]]|$1|L|3|-4|5|6|7|12|8|@]|9|@]|A|$]]|$1|M|3|N|5|O|7|13|8|@]|9|@]|A|$]]|$1|P|3|-4|5|6|7|14|8|@]|9|@]|A|$]]|$1|Q|3|R|5|6|7|15|8|@]|9|@]|A|$]]|$1|S|3|-4|5|6|7|16|8|@]|9|@]|A|$]]]|T|$]]

First check the version of JDK you are using, it should higher than 1.8.

If it is then proceed to do below steps.

Change Language level of Project and modules in Intellij.

Project

<blockquote>
 1.File->Project Structure->Project->Project language level
 Change it to 8 for lamba expressions to work
 
 2.File->Project Structure->Module->Project language level
 Change it to 8 for lamba expressions to work
</blockquote>

blocks|key|161290|text|这回答了新更新的intelliJ不起作用的问题...对于新的intelliJ..|type|unstyled|depth|inlineStyleRanges|entityRanges|data|161291|转到-->文件-->项目结构-->全局库==>设置为JDK1.8或更高版本。|161292|另外，文件--+>项目结构->+projects+===>将“项目语言手册”设置为8|161293|另请参阅文件--+>项目结构->项目sdk+==>+1.8|161294|这将为您的项目启用lambda表达式。|161295|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|M|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|N|8|@]|9|@]|A|$]]|$1|F|3|G|5|6|7|O|8|@]|9|@]|A|$]]|$1|H|3|I|5|6|7|P|8|@]|9|@]|A|$]]|$1|J|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|K|$]]

this answers not working for new updated intelliJ... for new intelliJ..

Go to --> file --> Project Structure --> Global Libraries ==> set to JDK 1.8 or higher version. 

also File -- > project Structure ---> projects ===> set "project language manual" to 8 

also File -- > project Structure ---> project sdk ==> 1.8

This should enable lambda expression for your project.

I was testing out some new features of Java 8 and copied the example into my IDE (Eclipse originally, then IntelliJ) as shown <a href="http://docs.oracle.com/javase/tutorial/java/javaOO/examples/RosterTest.java" rel="noreferrer">here</a>

Eclipse offered no support whatsoever for lambda expressions, and IntelliJ kept reporting an error 

<blockquote>
 Lambda expressions not supported at this language level
</blockquote>

I would like to know if this is a problem with my install, the code, or support.

Java "lambda expressions not supported at this language level"

集成开发环境

Android Studio

IntelliJ IDEA

编译器

Android

Eclipse

Ubuntu

Java

我测试了Java8的一些新特性，并将示例复制到我的集成开发环境中(最初是Eclipse，然后是IntelliJ)，如所示Eclipse不提供对lambda表达式的任何支持，而IntelliJ一直报告错误此语言级别不支持 Lambda表达式我想知道这是否是我的安装、代码或支持方面的问题。

问Java“此语言级别不支持lambda表达式”
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