Gradle "Entry .classpath is a duplicate but no duplicate handling strategy has been set"

Question

I'm trying to build a gradle project but, when I try $ gradle build I get the following output:

Starting a Gradle Daemon (subsequent builds will be faster) > Task :jar FAILED FAILURE: Build failed with an exception. * What went wrong: Execution failed for task ':jar'. > Entry .classpath is a duplicate but no duplicate handling strategy has been set. Please refer to https://docs.gradle.org/7.0/dsl/org.gradle.api.file.CopySpec.html#org.gradle.api.file.CopySpec:duplicatesStrategy for details. * Try: Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights. * Get more help at https://help.gradle.org BUILD FAILED in 11s 4 actionable tasks: 2 executed, 2 up-to-date

After doing Get-ChildItem -Path ./ -Filter .classpath -Recurse -Force I concluded that I don't even have a single file named .classpath in my project. What do I do?

If you're on linux or OSX, try: find . -name .classpath -type f in the root folder of your project — tim_yates
– tim_yates, Commented Apr 26, 2021 at 10:57
Just checked this. I don't have any .classpath in my project — 136
– 136, Commented Apr 26, 2021 at 11:19
Also note that if the error is about an Entry classpath.index instead of .classpath (google shows this question as first answer then), it's a problem caused by intellij. see: github.com/gradle/gradle/issues/17236. The "entry" is actually a file which exists with the same name in different folders, this is not very clear from the error message. — Daniel Alder
– Daniel Alder, Commented Jan 10, 2023 at 10:06
@DanielAlder, thanks for your comment. It helped me a lot. I had exactly this problem. — Mr. BoFrost
– Mr. BoFrost, Commented Jan 12, 2023 at 8:19

João Carlos · Accepted Answer · 2021-08-25 12:13:52Z

87

Similar to @korn answer, I solved mine using the EXCLUDE Strategy;

tasks.withType<Jar>() { duplicatesStrategy = DuplicatesStrategy.EXCLUDE manifest { attributes["Main-Class"] = "MainKt" } configurations["compileClasspath"].forEach { file: File -> from(zipTree(file.absoluteFile)) } }

answered Aug 25, 2021 at 12:13

João Carlos

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3 Comments

prayagupadhyay Over a year ago

how can conflicts be MERGED?

benone Over a year ago

Added duplicatesStrategy = DuplicatesStrategy.EXCLUDE and it works! Magic!

JavaDev1987 Over a year ago

this one is not working

Jakub Zalas · Accepted Answer · 2023-01-27 15:30:11Z

64

jar { duplicatesStrategy(DuplicatesStrategy.EXCLUDE) }

edited Jan 27, 2023 at 15:30

Jakub Zalas

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answered Dec 13, 2021 at 18:46

Marina Mikilchenko

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3 Comments

nouveu Over a year ago

For people using Spring Boot plugin: replace jar with bootJar.

frblazquez Over a year ago

Similar for my case with java gradle plugin: replace jar with sourcesJar

JavaDev1987 Over a year ago

this one is not working

wprogLK · Accepted Answer · 2023-01-05 09:03:17Z

29

I was having the same issues while executing some tests in IntelliJ. What helped me was just run a simple gradle clean.

answered Jan 5, 2023 at 9:03

wprogLK

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1 Comment

Yazid Over a year ago

This one solved my case. Clean slate start sometimes did the trick.

Morteza · Accepted Answer · 2022-07-01 09:30:16Z

17

Please add this

tasks.withType(Copy).all { duplicatesStrategy 'exclude' }

In the build.gradle file then solved it.

edited Jul 1, 2022 at 9:30

answered Jun 20, 2022 at 9:44

Morteza

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3 Comments

Steve Over a year ago

Please avoid to start an answer with I have the same problem because you risk to have it flagged as Not An Answer. Instead use a more affirmative text like To solve the problem you should .....

Mia Over a year ago

tasks.withType<Jar> doesn't work for me, this Copy does

Florian F Over a year ago

This one worked for me. It seems to depend on which task experiences a conflict.

korn · Accepted Answer · 2021-06-11 08:40:36Z

8

I faced same issue while building with kotlin and gradle 7. Resolve the issue adding the below code to your build.gradle.kts.

tasks.withType<Jar> { duplicatesStrategy = DuplicatesStrategy.INHERIT }

answered Jun 11, 2021 at 8:40

korn

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3 Comments

Brian White Over a year ago

INHERIT didn't work for me but EXCLUDE did.

devatherock Over a year ago

DuplicatesStrategy.INHERIT is already the default in gradle 7 - docs.gradle.org/7.5.1/dsl/…, so setting it to the same value again might not make any difference

JavaDev1987 Over a year ago

this one is not working

yatsvic · Accepted Answer · 2021-04-30 14:12:42Z

If you use Kotlin DSL and Gradle 7.0 it may be due to that bug KT-46165 It should be fixed in version 1.5.0.

Kirill · Accepted Answer · 2021-07-01 11:29:25Z

Do not know about your case with .classpath file which you can not even find (as I know this file is usually created with Eclipse IDE which I do not use)

But I faced the same error upgrading Spring Boot app to Gradle 7.x. My build script had additional resources processing task to support @..@-style placeholders (like Spring Boot Maven build does, cause for now I support both build systems in the project and I need them to behave equal):

processResources { with copySpec { from 'src/main/resources' include 'my-app*.yml' include 'my-app*.yaml' include 'my-app*.properties' project.properties.findAll().each { prop -> if (prop.value != null) { filter(ReplaceTokens, tokens: [(prop.key): prop.value.toString()]) } } } }

I got the same error with Gradle 7:

Entry my-app.properties is a duplicate but no duplicate handling strategy has been set. Please refer to https://docs.gradle.org/7.1/dsl/org.gradle.api.tasks.Copy.html#org.gradle.api.tasks.Copy:duplicatesStrategy for details.

And, indeed, there is a duplicate. Gradle first copies unprocessed file to build/resources/main and later tries to execute my custom processResources and copy files again to the same place.

The solution was adding duplicatesStrategy = 'include' to with copySpec {} block. Looks like previously Gradle silently overwrote the duplicate so there was no problem.

miracle_the_V · Accepted Answer · 2023-05-24 09:59:30Z

In my case, there was a com.sun.xml.ws:jaxws-rt exposed through dependency, while my project uses org.glassfish.jaxb:jaxb-runtime

Both resulted in jar with the same name (jaxb-core.jar) in classpath.

Removing com.sun.xml.ws:jaxws-rt from dependency helped. Fortunately, depencency was in my control.

Akhil Joy · Accepted Answer · 2023-11-16 02:41:18Z

Go to build.gradle file and add the following

tasks.named("jar") { duplicatesStrategy = DuplicatesStrategy.EXCLUDE exclude("classpath.index") }

faraz naeem · Accepted Answer · 2022-11-06 18:33:17Z

check your app level build gradle and look if you did not enter font name twice in folloing lineproject.ext.vectoricons = [ iconFontNames: [ 'FontAwesome.ttf','FontAwesome5_Brands.ttf','FontAwesome5_Regular.ttf','FontAwesome5_Solid.ttf',"Foundation.ttf","Ionicons.ttf","MaterialIcons.ttf","MaterialCommunityIcons.ttf","AntDesing.ttf","Entypo.ttf","EvilIcons.ttf","Feather.ttf","FontAwesome5.ttf","SimpleLineIcons.ttf","Octicons.ttf"] // Name of the font files you want to copy ] remove if you have any duplicate name entry worked for me

Dani Pralea · Accepted Answer · 2023-05-13 10:00:28Z

0

tasks.getByName<Jar>("jvmJar") { duplicatesStrategy = DuplicatesStrategy.EXCLUDE }

answered May 13, 2023 at 10:00

Dani Pralea

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Comments

SHASHANK AGRAWAL · Accepted Answer · 2023-06-19 06:29:41Z

I was having same error, while building elastic search repository. Deleting the build files in build-tools-internal folder worked for me somehow.

mozway · Accepted Answer · 2024-03-06 14:23:40Z

In my case even after adding exclude did not work.

I havd to manually delete the META-INF file from src folder and to rebuild from terminal to solve the issue.

Kwami · Accepted Answer · 2024-10-12 22:48:35Z

Check the build directory if classpath.index exists. if it does. delete it and rebuild the project.

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