Нормальная модульная структура

lib/.gitignore

@@ -0,0 +1 @@
+/build

lib/build.gradle.kts

@@ -0,0 +1,9 @@
+plugins {
+    id("java-library")
+    alias(libs.plugins.jetbrains.kotlin.jvm)
+}
+
+java {
+    sourceCompatibility = JavaVersion.VERSION_21
+    targetCompatibility = JavaVersion.VERSION_21
+}

lib/src/main/java/com/example/lib/MyClass.kt

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+package com.example.lib
+
+class MyClass {
+    val test: java.time.LocalDate;
+}