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Android Java Project Converts to Kotlin in Android Studio

Posted by: admin June 15, 2020 Leave a comment


I want to convert my java project to Kotlin, there are more than 500 java files. How can I convert it into Kotlin easily?

I know that we can convert one by one java file to Kotlin, But there are many files.

Can I convert it at once?

How to&Answers:

You can definitely try. You just need to select a module or a folder in the Project navigator and select Code --> Convert Java file to Kotlin file:

Convert complete module to Kotlin

You, though, need to keep in mind that the conversion is not perfect. For instance, Android Studio will have to guess whether a whole lot of properties are nullable or not. It will not get them all right… you will get a lot of crashes.

My suggestion would be to batch files in sensible chunks, so you can fix those Kotlinized files without getting swamped with errors.

Note: after converting a file to Kotlin you still will need to review it. A lot of things will be kept in Java for the sake of safety, but now that you have Kotlin you can use collection extensions, default constructor parameters, …


  1. Select your app folder and go to Code Convert Java File to Kotlin File

  2. Then after you convert the file,it says kotlin not configured.Click the Configure text then select the type of module you want to apply kotlin and it comes with the latest kotlin version press ok

N.B After you convert the code,you must convert some parameters that the compiler found it as a warning or error message.


It’s easy, android-studio will do most of the work for you. To convert the existing javacode into kotlin, simply select the src/main/java folder in the project and choose Code->“Convert Java File to Kotlin File”. Android studio will then try as best as it can to convert all your java-code to kotlin-code.