Added test to make sure no processing is done for Java DTO

Author: k163377

src/test/kotlin/com/fasterxml/jackson/module/kotlin/test/github/GitHub922.kt

@@ -0,0 +1,32 @@
+package com.fasterxml.jackson.module.kotlin.test.github
+
+import com.fasterxml.jackson.databind.BeanDescription
+import com.fasterxml.jackson.databind.ObjectMapper
+import com.fasterxml.jackson.module.kotlin.KotlinFeature
+import com.fasterxml.jackson.module.kotlin.jacksonObjectMapper
+import org.junit.jupiter.api.Assertions.assertTrue
+import kotlin.test.Test
+
+class GitHub922 {
+    private inline fun <reified T : Any> ObjectMapper.introspectSerialization(): BeanDescription =
+        serializationConfig.introspect(serializationConfig.constructType(T::class.java))
+
+    private inline fun <reified T : Any> ObjectMapper.introspectDeserialization(): BeanDescription =
+        deserializationConfig.introspect(deserializationConfig.constructType(T::class.java))
+
+    private fun BeanDescription.isRequired(propertyName: String): Boolean =
+        this.findProperties().first { it.name == propertyName }.isRequired
+
+    @Test
+    fun `nullToEmpty does not override specification by Java annotation`() {
+        val mapper = jacksonObjectMapper {
+            enable(KotlinFeature.NullToEmptyCollection)
+            enable(KotlinFeature.NullToEmptyMap)
+        }
+
+        val desc = mapper.introspectDeserialization<GitHub922RequiredCollectionsDtoJava>()
+
+        assertTrue(desc.isRequired("list"))
+        assertTrue(desc.isRequired("map"))
+    }
+}

src/test/kotlin/com/fasterxml/jackson/module/kotlin/test/github/GitHub922RequiredCollectionsDtoJava.java

@@ -0,0 +1,29 @@
+package com.fasterxml.jackson.module.kotlin.test.github;
+
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonProperty;
+
+import java.util.List;
+import java.util.Map;
+
+public class GitHub922RequiredCollectionsDtoJava {
+    private final List<String> list;
+    private final Map<String, String> map;
+
+    @JsonCreator
+    public GitHub922RequiredCollectionsDtoJava(
+            @JsonProperty(value = "list", required = true) List<String> list,
+            @JsonProperty(value = "map", required = true) Map<String, String> map
+    ) {
+        this.list = list;
+        this.map = map;
+    }
+
+    public List<String> getList() {
+        return list;
+    }
+
+    public Map<String, String> getMap() {
+        return map;
+    }
+}