Android Studio I keep getting Gradle error “The process cannot access the file because it is being used by another process”

Question

I can import a sample app project, try to build it and I keep getting this error. Not always the same file but a new temp file each time. I\'ve tried several different sampl

Answer 1

If the error is recurring, you can try a file leak detector to determine what part of the gradle process is holding your files. As suggested here,

1. Download file leak detector

2. Check with resmon what process is holding on to the file

3. Depending on where the file is locked, do the following:

   • Android Studio: In studio, go to Help → Edit custom VM options and add the following line:

     -javaagent:path/to/file-leak-detector.jar=http=19999
     

   • Gradle: Add to your gradle.properties file the following line:

     org.gradle.jvmargs=-javaagent:path/to/file-leak-detector.jar=http=19999
     

4. When the problem occurs again, open localhost:19999 in your browser and search for locked files.

---

In my case, I found out that a file was held by AspectJ compiler/weaver (ajc):

#115 C:\Users\me\StudioProjects\myapp\app\build\intermediates\compile_and_runtime_not_namespaced_r_class_jar\debug\R.jar by thread:Execution worker for ':' Thread 3 on Mon Oct 19 18:41:06 BST 2020
    at java.util.zip.ZipFile.(ZipFile.java:156)
    ...
    at org.aspectj.tools.ajc.Main$run.call(Unknown Source)

I was running it directly from Gradle:

new Main().run(args, handler)

I don't know if it's possible to make ajc release the files. So I resolved my issue by running it in a separate process. I added a new configuration to get aspectjtools onto classpath:

val weaving: Configuration by configurations.creating

dependencies {
    weaving("org.aspectj:aspectjtools:1.9.6")
}

And instead of the above code, I did:

javaexec {
    classpath = weaving
    main = "org.aspectj.tools.ajc.Main"
    args = arguments
}