Java "lambda expressions not supported at this language level"

Question

I was testing out some new features of Java 8 and copied the example into my IDE (Eclipse originally, then IntelliJ) as shown here

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

Lambda expressions not supported at this language level

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

It's an IDE issue. You have to change your compiler compliance. — Sotirios Delimanolis, Mar 28 '14 at 03:06
In IDEA, select File -> Project structure; you'll have the option to change the language level — fge, Mar 28 '14 at 03:06
@Czipperz: On SO don't annotate the title with "Solved", mark the best answers as "Accepted" by clicking the tick. That rewards the answerer and shows the question has an answer which resolves the problem. If no answer gives the right resolution, you are free to post a self-answer and then mark it accepted (after a waiting period). — Lawrence Dol, Mar 28 '14 at 03:23
possible duplicate of [How do I use Java 8 features in Eclipse Luna?](http://stackoverflow.com/questions/22668739/how-do-i-use-java-8-features-in-eclipse-luna) — Svetlin Zarev, Mar 28 '14 at 07:57
@LawrenceDol I annotated it like that because they didn't post it as an answer, but as a comment. — Czipperz, Mar 28 '14 at 20:36
Well this is for IntelliJ as well, but thanks for the support for Eclipse @SvetlinZarev — Czipperz, Mar 28 '14 at 20:37
do you use some kind of build tools? (maven, etc.) - the preferred setup might be different — voho, Nov 06 '15 at 08:49
*"Eclipse offered no support whatsoever for lambda expressions"*- This is patently incorrect, and was incorrect when the question was asked; see my answer and others that tell you how to get it. — Stephen C, Mar 23 '19 at 23:41

score 400 · Accepted Answer · edited May 28 '19 at 22:24

400

In IntelliJ IDEA:

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

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

Screenshot:

edited May 28 '19 at 22:24

Asad Ali Choudhry

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answered Mar 28 '14 at 05:05

Abhilash Divakaran

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**Note from proposed edit**: You can also configure language level for every module, `File Menu → Project Structure → Modules`, but by default it will the same as Project language level. – user1516873 May 14 '15 at 16:18
6

I'm facing same issue for Android Studio and neither found same settings in IDE you mention above. Any suggestion ! – CoDe Sep 02 '15 at 06:49
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@Shubh: In Gradle, add these lines, your code will work: `android { compileOptions { sourceCompatibility JavaVersion.VERSION_1_8 targetCompatibility JavaVersion.VERSION_1_8 } }` – BaDo Sep 25 '15 at 02:30
7

After **upgrading** to **IntelliJ 15**, I had to change the *Project Language Level* up to 9 and then back to 8 for that to take effect. – averasko Nov 03 '15 at 14:29
2

In maven, you have to explicitly set to 1.8 language level. http://stackoverflow.com/questions/16723533/how-do-you-specify-the-java-compiler-version-in-a-pom-xml-file – mjlee Jan 10 '16 at 16:32
3

does not exist on AS1.5.1 on Mac – Jemshit May 13 '16 at 12:48
I was facing the same issue but it was already on 8.0. The comment from @user1516873 helped me solve the issue – Ced Jun 21 '16 at 22:51
18

This answer is outdated. On Android 3.1.2 go to ```File``` -> ```Project Structure``` -> ```Module you want to support lambdas``` and set **Source Compatibility** and **Target Compatibility** to **1.8** – Ivan May 18 '18 at 20:25
@Ivan yes thank you for the updated version, I've been searching for so long, [this is](https://developer.android.com/studio/intro/studio-config#jdk) the same thing but not UI – Roshna Omer Sep 06 '18 at 07:20
1

In Android Studio, it's File--Project Structure, select App under Module, Properties Tab, then set Source Compability to 1.8. Oh already mentioned above by Ivan – GeoffL Mar 19 '19 at 10:14
On Android Studio 3.6.3, my screen showed 1.8 supported but I was getting the compiler error. I read @averasko comment and switched my setting to 1.7, applied, then switched back to 1.8 and applied, and the compile error went away. Thanks! – Mike Aug 05 '20 at 15:06

score 106 · Answer 2 · edited Jan 10 '17 at 16:49

106

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

edited Jan 10 '17 at 16:49

Jordi Castilla

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answered May 29 '15 at 06:12

dmitry.bogatko

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your answer should be higher or together with other answers – Anton Krug Mar 01 '16 at 14:42
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+1. The priority of modules is higher than the project's. So I prefer setting the language level of modules part. – Ge Liu May 06 '16 at 14:56
This doesn't include the module which IntelliJ also requires. Not crazy about this side of IntelliJ, too many places to check the same thing. – SpacePrez Sep 19 '17 at 21:36
Awesome. Thank you so much. This saved my day. I was struggling with the error not sure what needs to be done to enable the lambda expressions. – Sidd Thota Oct 24 '17 at 22:27
I was running a spring boot ap, and not sure what went wrong after I started using lambda expressions, I changed the project settings, but after following this modules setting, It worked fine. – Sidd Thota Oct 25 '17 at 00:13
Thanks alot for screen shot, I was wondering as I have Language Level 8 already selected in File Menu → Project Structure → Project, change Project Language Level and it was not working. Your screen shot save my day! – Fahad Dec 08 '17 at 05:16

score 80 · Answer 3 · edited Apr 19 '19 at 04:50

This solution works in Android Studio 3.0 or later.

File > Project Structure > Modules > app > Properties tab

Change both of Source Compatibility and Target Compatibility to 1.8

Edit config file

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

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
  }
}

prayagupa · Answer 4 · 2017-02-03T21:56:20.817

45

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

File
|
|
 ---------Project Structure -> Project tab
          |
          |________Project language level

java8

Module lang level

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

File
|
|
 ---------Project Structure -> Modules tab
          |
          |________ language level

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

    <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>

After changes everything looks good

edited Feb 03 '17 at 21:56

answered Mar 28 '15 at 23:05

prayagupa

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@Czipperz: This answer has pictures. I prefer it, because I had actually already looked at the spot the accepted answer mentioned but failed to notice the dropdown. This answer has pictures highlighting the exact spot where the option is. – ArtOfWarfare Apr 16 '15 at 21:10
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the part about pom.xml file is really helpful, thanks! – Kevin Zhao Apr 21 '17 at 18:24
3

After changing language level also for module fixed my problem – nihasmata Sep 08 '17 at 11:56
This did the trick for me, i.e. the language level. – Jack BeNimble Jul 18 '20 at 23:00

Tarun Deep Attri · Answer 5 · 2017-11-08T10:20:22.177

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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.

edited Nov 08 '17 at 10:20

answered Nov 06 '17 at 09:12

Tarun Deep Attri

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score 20 · Answer 6 · answered Dec 30 '16 at 12:41

20

Just add compileOptions in build.gradle yours app:

android {


...

  defaultConfig {
    ...
    jackOptions {
      enabled true
    }
  }
  compileOptions {
    sourceCompatibility JavaVersion.VERSION_1_8
    targetCompatibility JavaVersion.VERSION_1_8
  }
}

answered Dec 30 '16 at 12:41

Morozov

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Google announced that they deprecating Jack a few weeks ago. Java 8 language features support is now natively provided by the Android Gradle plugin, starting with Android Studio 2.4 Preview 4. Look [here](https://issuetracker.google.com/issues/37126573#comment2) – nilsi Apr 20 '17 at 06:18

score 10 · Answer 7 · answered Dec 16 '17 at 09:44

10

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.

answered Dec 16 '17 at 09:44

Vivek

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easy and better than others – Abhishek Singh Jan 12 '18 at 05:16

score 7 · Answer 8 · answered May 17 '18 at 18:36

7

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

answered May 17 '18 at 18:36

Kejsi Struga

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score 5 · Answer 9 · answered Jan 30 '19 at 15:37

5

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

compileOptions {
    targetCompatibility 1.8
    sourceCompatibility 1.8
}

answered Jan 30 '19 at 15:37

live-love

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score 2 · Answer 10 · answered Mar 28 '14 at 03:21

2

Actually, Eclipse support for Java 8 is available: see here and here.

For Kepler, it is available as a "feature patch" against SR2 (i.e. Eclipse 4.3.2)
For Luna (Eclipse 4.4) it will be in the standard release. (release schedule)

answered Mar 28 '14 at 03:21

Stephen C

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score 2 · Answer 11 · answered Jan 07 '16 at 00:15

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

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

score 2 · Answer 12 · answered Aug 22 '17 at 15:20

Using: IntelliJ IDEA 2017.1.4 Build #IU-171.4694.23

Changing the language level via the Project Settings / Project tab didn't do anything. Instead hitting Alt + Enter and selecting "Set language level to 8 - Lambdas, type annotations etc." and it resolved automatically.

score 1 · Answer 13 · answered Mar 28 '14 at 07:54

As Stephen C pointed out, Eclipse Kepler (4.3) has Java 8 support when the patch is installed (installation instructions here)

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

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

Then tell the project to use JDK 1.8:

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

score 1 · Answer 14 · answered Nov 02 '18 at 17:17

Check below settings:

File->Project Structure->Project Tab.

*Project SDK should be set to 8 or above.*

File->Project Structure->Modules.

*Check that your or all modules has Language level set to 8 or above.*

File->Settings(or Other Settings->Preference for new projects in newer Idea version)

*Search for Java compiler and check if Project byte code version 
and per module byte code version is set 8 or above.*

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

score 1 · Answer 15 · answered Apr 02 '19 at 05:59

The same project (Android Studio 3.3.2, gradle-4.10.1-all.zip, compileSdkVersion 28, buildToolsVersion '28.0.3') works fine on the new fast Windows machine and underline Java 8 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 incremental true and dexOptions

compileOptions {
//    incremental true
    sourceCompatibility JavaVersion.VERSION_1_8
    targetCompatibility JavaVersion.VERSION_1_8
}

//dexOptions {
//    javaMaxHeapSize "4g"
//}

in the app- level build.gradle.

score 0 · Answer 16 · edited Jan 08 '16 at 04:51

0

In intellij 14, following settings worked for me. Intellij14 Settings

edited Jan 08 '16 at 04:51

Manjunath Ballur

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answered Jan 08 '16 at 03:54

user5760784

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score 0 · Answer 17 · answered Aug 15 '16 at 20:06

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:

<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>

kuzevni · Answer 18 · 2016-11-06T00:04:12.807

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

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.
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).

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

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.

Best wishes :)

This is for people using google to check for already solved problems. People who work in the industry knows this. — kuzevni, Nov 06 '16 at 00:34

score 0 · Answer 19 · answered Nov 20 '17 at 00:24

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.

score 0 · Answer 20 · answered Feb 03 '21 at 13:25

0

Adding below lines in app level build.gradle in Android project solved issue.

 compileOptions {
        sourceCompatibility = JavaVersion.VERSION_1_8
        targetCompatibility = JavaVersion.VERSION_1_8
    }

answered Feb 03 '21 at 13:25

Tarun Anchala

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score 0 · Answer 21 · answered Oct 26 '22 at 08:13

0

File > Project Structure > Modules > Source tab> Change Language level to 8

answered Oct 26 '22 at 08:13

Abd Abughazaleh

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score -1 · Answer 22 · answered Sep 18 '16 at 11:04

-1

Ctrl + Alt + Shift + S and then from project select the language level 1.8, read more about Lambda Expressions here

answered Sep 18 '16 at 11:04

Toseef Zafar

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score -1 · Answer 23 · answered May 07 '18 at 19:15

To have support of Ecplise for lambda expressions :

Make sure you are using JDK 1.8 (Window > Preferences > Installed JREs and Compiler );
Use the annotation @FunctionalInterface if you define any new functional interfaces so that eclipse will suggest you refactorings related to Lambdas ( Functional Interfaces. )

score -1 · Answer 24 · edited Sep 06 '18 at 07:34

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

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

score -1 · Answer 25 · answered Feb 14 '19 at 17:38

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.

Java "lambda expressions not supported at this language level"

25 Answers25

Module lang level

Linked

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