# Convert interface (java) to fun interface (kotlin)

**URL:** <https://discuss.kotlinlang.org/t/convert-interface-java-to-fun-interface-kotlin/25545>\
**Category:** Language Design\
**Created:** [August 27, 2022, 8:34pm UTC](https://discuss.kotlinlang.org/t/convert-interface-java-to-fun-interface-kotlin/25545 "2022-08-27T20:34:34Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![vadimskyagogvangok](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.kotlinlang.org/vadimskyagogvangok/32/9481_2.png) [@vadimskyagogvangok](https://discuss.kotlinlang.org/u/vadimskyagogvangok)\
**Post date:** [August 27, 2022, 8:34pm UTC](https://discuss.kotlinlang.org/t/convert-interface-java-to-fun-interface-kotlin/25545/1 "2022-08-27T20:34:34Z")

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If the programmer forgot to write @FunctionalInterface, java code is converted to interface, even if it only has 1 method. I think if an interface (java) has only 1 method it should be converted to fun interface (kotlin).

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**Author:** ![broot](https://avatars.discourse-cdn.com/v4/letter/b/a88e57/32.png) [@broot](https://discuss.kotlinlang.org/u/broot)\
**Post date:** [August 27, 2022, 9:11pm UTC](https://discuss.kotlinlang.org/t/convert-interface-java-to-fun-interface-kotlin/25545/2 "2022-08-27T21:11:13Z")

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What case do you mean exactly? Kotlin doesn’t require `@FunctionalInterface` in order to use SAM conversions. You can use any interface with a single abstract method as a function.

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**Author:** ![vadimskyagogvangok](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.kotlinlang.org/vadimskyagogvangok/32/9481_2.png) [@vadimskyagogvangok](https://discuss.kotlinlang.org/u/vadimskyagogvangok)\
**Post date:** [August 27, 2022, 9:46pm UTC](https://discuss.kotlinlang.org/t/convert-interface-java-to-fun-interface-kotlin/25545/3 "2022-08-27T21:46:24Z")

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I’m talking about converting code from Java to Kotlin (intellij idea).