<div class="type-placeholder" style="font-size: 15px; letter-spacing: -0.3px; color: #abb0b5; white-space: pre-wrap;">&nbsp;</div>
<div class="type-placeholder" style="font-size: 15px; letter-spacing: -0.3px; color: #abb0b5; white-space: pre-wrap;">&nbsp;</div>
<div class="type-placeholder" style="font-size: 15px; letter-spacing: -0.3px; color: #abb0b5; white-space: pre-wrap;"><span style="color: #000000;"><span style="color: #abb0b5;"><span style="font-size: 15px; letter-spacing: -0.3px; white-space: pre-wrap;">저도 안돼서 찾아보니 버전이 달라서 생긴 오류입니다. </span></span></span></div>
<div class="type-placeholder" style="font-size: 15px; letter-spacing: -0.3px; color: #abb0b5; white-space: pre-wrap;"><span style="color: #000000;"><span style="color: #abb0b5;"><span style="font-size: 15px; letter-spacing: -0.3px; white-space: pre-wrap;">강사님 소스 그대로 복붙해도 안되더라구요</span></span></span></div>
<div class="type-placeholder" style="font-size: 15px; letter-spacing: -0.3px; color: #abb0b5; white-space: pre-wrap;">&nbsp;</div>
<div class="type-placeholder" style="font-size: 15px; letter-spacing: -0.3px; color: #abb0b5; white-space: pre-wrap;"><span style="color: #000000;"><span style="color: #abb0b5;"><span style="font-size: 15px; letter-spacing: -0.3px; white-space: pre-wrap;">저같은 경우에는 gradle에서 </span></span></span></div>
<div class="type-placeholder" style="font-size: 15px; letter-spacing: -0.3px; color: #abb0b5; white-space: pre-wrap;"><span style="color: #000000;"><span style="color: #abb0b5;"><span style="font-size: 15px; letter-spacing: -0.3px; white-space: pre-wrap;">implementation 'androidx.core:core-ktx:1.7.0' 에서</span></span></span></div>
<div class="type-placeholder" style="font-size: 15px; letter-spacing: -0.3px; color: #abb0b5; white-space: pre-wrap;"><span style="color: #000000;"><span style="color: #abb0b5;"><span style="font-size: 15px; letter-spacing: -0.3px; white-space: pre-wrap;">implementation 'androidx.core:core-ktx:1.3.2' 로 </span></span></span></div>
<div class="type-placeholder" style="font-size: 15px; letter-spacing: -0.3px; color: #abb0b5; white-space: pre-wrap;"><span style="color: #000000;"><span style="color: #abb0b5;"><span style="font-size: 15px; letter-spacing: -0.3px; white-space: pre-wrap;">다운그레이드하니깐 잘 됐습니다. </span></span></span></div>
<div class="type-placeholder" style="font-size: 15px; letter-spacing: -0.3px; color: #abb0b5; white-space: pre-wrap;">&nbsp;</div>
<div class="type-placeholder" style="font-size: 15px; letter-spacing: -0.3px; color: #abb0b5; white-space: pre-wrap;"><span style="color: #000000;"><span style="color: #abb0b5;"><span style="font-size: 15px; letter-spacing: -0.3px; white-space: pre-wrap;">::class.java는 최신버전에서는 아무래도 안 되는 것 같네요. </span></span></span></div>
<div class="type-placeholder" style="font-size: 15px; letter-spacing: -0.3px; color: #abb0b5; white-space: pre-wrap;"><span style="color: #000000;"><span style="color: #abb0b5;"><span style="font-size: 15px; letter-spacing: -0.3px; white-space: pre-wrap;">안되는분들 참고하시면 좋을거같습니다</span></span></span></div>
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<div class="type-placeholder" style="font-size: 15px; letter-spacing: -0.3px; color: #abb0b5; white-space: pre-wrap;">&nbsp;</div>

<p>https://altongmon.tistory.com/658&nbsp; &nbsp;여기 보면 확장 플러그인 추가하라는데 다운그레이드보다는 이게 더 좋을지도 모르겠습니다!</p>

인프런 커뮤니티 질문&답변

밑에 ::class.java 안된다고 하신분