For collection types List, Set, Map use equals() rather than isAssign…

blackbox-test/src/main/java/org/example/customer/stream/MyArrayList.java

@@ -0,0 +1,9 @@
+package org.example.customer.stream;
+
+import io.avaje.jsonb.Json;
+
+import java.util.ArrayList;
+
+@Json
+public record MyArrayList(int id, ArrayList<String> names) {
+}

blackbox-test/src/main/java/org/example/customer/stream/MyLinked.java

@@ -0,0 +1,9 @@
+package org.example.customer.stream;
+
+import io.avaje.jsonb.Json;
+
+import java.util.LinkedHashSet;
+
+@Json
+public record MyLinked(int id, LinkedHashSet<String> names) {
+}

blackbox-test/src/test/java/org/example/customer/stream/MyArrayListTest.java

@@ -0,0 +1,30 @@
+package org.example.customer.stream;
+
+import io.avaje.jsonb.Jsonb;
+import org.junit.jupiter.api.Test;
+
+import java.util.ArrayList;
+import java.util.LinkedHashSet;
+import java.util.List;
+import java.util.Set;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+
+class MyArrayListTest {
+
+  Jsonb jsonb = Jsonb.builder().build();
+
+  @Test
+  void toJson_fromJson() {
+    MyArrayList myLinked = new MyArrayList(1, new ArrayList<>(List.of("a", "b", "c")));
+
+    String json = jsonb.toJson(myLinked);
+    assertNotNull(json);
+    assertThat(json).isEqualTo("{\"id\":1,\"names\":[\"a\",\"b\",\"c\"]}");
+
+    MyArrayList fromJson = jsonb.type(MyArrayList.class).fromJson(json);
+    assertEquals(myLinked, fromJson);
+  }
+}

blackbox-test/src/test/java/org/example/customer/stream/MyLinkedHashSetTest.java

@@ -0,0 +1,28 @@
+package org.example.customer.stream;
+
+import io.avaje.jsonb.Jsonb;
+import org.junit.jupiter.api.Test;
+
+import java.util.LinkedHashSet;
+import java.util.List;
+import java.util.Set;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.jupiter.api.Assertions.*;
+
+class MyLinkedHashSetTest {
+
+  Jsonb jsonb = Jsonb.builder().build();
+
+  @Test
+  void toJson_fromJson() {
+    MyLinked myLinked = new MyLinked(1, new LinkedHashSet<>(List.of("a", "b", "c")));
+
+    String json = jsonb.toJson(myLinked);
+    assertNotNull(json);
+    assertThat(json).isEqualTo("{\"id\":1,\"names\":[\"a\",\"b\",\"c\"]}");
+
+    MyLinked fromJson = jsonb.type(MyLinked.class).fromJson(json);
+    assertEquals(myLinked, fromJson);
+  }
+}

jsonb-generator/src/main/java/io/avaje/jsonb/generator/GenericType.java

@@ -167,22 +167,22 @@ private String asTypeBasic() {
     if (adapterType != null) {
       return adapterType;
     }
-    return Util.shortName(topType)+".class";
+    return Util.shortName(topType) + ".class";
   }
 
   private String asTypeContainer() {
     GenericType param = params.get(0);
     String containerType = topType();
-    if (isAssignable(containerType, "java.util.List")) {
+    if ("java.util.List".equals(containerType) || "java.util.ArrayList".equals(containerType)) {
       return "Types.listOf(" + Util.shortName(param.topType()) + ".class)";
     }
-    if (isAssignable(containerType, "java.util.Set")) {
+    if ("java.util.Set".equals(containerType) || "java.util.LinkedHashSet".equals(containerType)) {
       return "Types.setOf(" + Util.shortName(param.topType()) + ".class)";
     }
-    if (isAssignable(containerType, "java.util.stream.Stream")) {
+    if ("java.util.stream.Stream".equals(containerType)) {
       return "Types.streamOf(" + Util.shortName(param.topType()) + ".class)";
     }
-    if (isAssignable(containerType, "java.util.Optional")) {
+    if ("java.util.Optional".equals(containerType)) {
       return "Types.optionalOf(" + Util.shortName(param.topType()) + ".class)";
     }
     return null;