Collections.emptyXXX + Collections.singletonXXX => List/Set/Map.of

19 files changed, 76 insertions, 91 deletions

diff --git a/config-model/src/test/java/com/yahoo/config/model/MapConfigModelRegistryTest.java b/config-model/src/test/java/com/yahoo/config/model/MapConfigModelRegistryTest.java
index cb232c4f812..900799b86a1 100644
--- a/config-model/src/test/java/com/yahoo/config/model/MapConfigModelRegistryTest.java
+++ b/config-model/src/test/java/com/yahoo/config/model/MapConfigModelRegistryTest.java
@@ -7,7 +7,6 @@ import org.junit.jupiter.api.Test;
 import org.w3c.dom.Element;
 
 import java.util.Collection;
-import java.util.Collections;
 import java.util.List;
 
 import static org.junit.jupiter.api.Assertions.*;
@@ -47,7 +46,7 @@ public class MapConfigModelRegistryTest {
         }
 
         @Override
-        public List<ConfigModelId> handlesElements() { return Collections.singletonList(ConfigModelId.fromName("modelB")); }
+        public List<ConfigModelId> handlesElements() { return List.of(ConfigModelId.fromName("modelB")); }
         @Override
         public void doBuild(ModelB model, Element spec, ConfigModelContext modelContext) { }
     }
@@ -57,7 +56,7 @@ public class MapConfigModelRegistryTest {
             super(ModelB.class);
         }
         @Override
-        public List<ConfigModelId> handlesElements() { return Collections.singletonList(ConfigModelId.fromName("modelB")); }
+        public List<ConfigModelId> handlesElements() { return List.of(ConfigModelId.fromName("modelB")); }
         @Override
         public void doBuild(ModelB model, Element spec, ConfigModelContext modelContext) { }
     }
@@ -73,7 +72,7 @@ public class MapConfigModelRegistryTest {
             super(ModelA.class);
         }
         @Override
-        public List<ConfigModelId> handlesElements() { return Collections.singletonList(ConfigModelId.fromName("modelA")); }
+        public List<ConfigModelId> handlesElements() { return List.of(ConfigModelId.fromName("modelA")); }
 
         @Override
         public void doBuild(ModelA model, Element spec, ConfigModelContext modelContext) { }
diff --git a/config-model/src/test/java/com/yahoo/config/model/provision/HostsXmlProvisionerTest.java b/config-model/src/test/java/com/yahoo/config/model/provision/HostsXmlProvisionerTest.java
index 51574432e6d..02ca9effffb 100644
--- a/config-model/src/test/java/com/yahoo/config/model/provision/HostsXmlProvisionerTest.java
+++ b/config-model/src/test/java/com/yahoo/config/model/provision/HostsXmlProvisionerTest.java
@@ -8,7 +8,6 @@ import org.junit.jupiter.api.Test;
 import java.io.StringReader;
 import java.util.ArrayList;
 import java.util.Collection;
-import java.util.Collections;
 import java.util.HashSet;
 import java.util.LinkedHashMap;
 import java.util.List;
@@ -22,27 +21,29 @@ import static org.junit.jupiter.api.Assertions.*;
  */
 public class HostsXmlProvisionerTest {
 
-    private static final String oneHost = "<?xml version=\"1.0\" encoding=\"utf-8\"?>\n" +
-            "<hosts>\n" +
-            "    <host name=\"test1.yahoo.com\">\n" +
-            "        <alias>node1</alias>\n" +
-            "        <alias>node2</alias>\n" +
-            "    </host>\n" +
-            "</hosts>";
-
-    private static final String threeHosts = "<?xml version=\"1.0\" encoding=\"utf-8\"?>\n" +
-            "<hosts>\n" +
-            "    <host name=\"test1.yahoo.com\">\n" +
-            "        <alias>node1</alias>\n" +
-            "    </host>\n" +
-            "    <host name=\"test2.yahoo.com\">\n" +
-            "        <alias>node2</alias>\n" +
-            "        <alias>node3</alias>\n" +
-            "    </host>\n" +
-            "    <host name=\"test3.yahoo.com\">\n" +
-            "        <alias>node4</alias>\n" +
-            "    </host>\n" +
-            "</hosts>";
+    private static final String oneHost = """
+            <?xml version="1.0" encoding="utf-8"?>
+            <hosts>
+                <host name="test1.yahoo.com">
+                    <alias>node1</alias>
+                    <alias>node2</alias>
+                </host>
+            </hosts>""";
+
+    private static final String threeHosts = """
+            <?xml version="1.0" encoding="utf-8"?>
+            <hosts>
+                <host name="test1.yahoo.com">
+                    <alias>node1</alias>
+                </host>
+                <host name="test2.yahoo.com">
+                    <alias>node2</alias>
+                    <alias>node3</alias>
+                </host>
+                <host name="test3.yahoo.com">
+                    <alias>node4</alias>
+                </host>
+            </hosts>""";
 
     @Test
     void require_basic_works() {
@@ -57,7 +58,7 @@ public class HostsXmlProvisionerTest {
         assertTrue(map.keySet().containsAll(aliases));
 
         // 5 services, 3 host aliases, mapping to 2 host.
-        aliases = createAliases(Collections.singletonList("node3"));
+        aliases = createAliases(List.of("node3"));
         map = allocate(hostProvisioner, aliases);
 
         assertCorrectNumberOfHosts(map, 2);
@@ -65,7 +66,7 @@ public class HostsXmlProvisionerTest {
         assertTrue(map.keySet().containsAll(aliases));
 
         // 5 services, 3 host aliases, mapping to 3 host.
-        aliases = createAliases(Collections.singletonList("node4"));
+        aliases = createAliases(List.of("node4"));
         map = allocate(hostProvisioner, aliases);
         assertEquals(3, map.size());
         assertCorrectNumberOfHosts(map, 3);
diff --git a/config-model/src/test/java/com/yahoo/config/model/provision/SingleNodeProvisionerTest.java b/config-model/src/test/java/com/yahoo/config/model/provision/SingleNodeProvisionerTest.java
index e5dca4e5adf..b4f586e3f2f 100644
--- a/config-model/src/test/java/com/yahoo/config/model/provision/SingleNodeProvisionerTest.java
+++ b/config-model/src/test/java/com/yahoo/config/model/provision/SingleNodeProvisionerTest.java
@@ -12,7 +12,6 @@ import org.xml.sax.SAXException;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Collection;
-import java.util.Collections;
 import java.util.HashSet;
 import java.util.LinkedHashMap;
 import java.util.List;
@@ -40,7 +39,7 @@ public class SingleNodeProvisionerTest {
         assertTrue(map.keySet().containsAll(aliases));
 
         // 5 services, 3 host aliases, mapping to 2 host.
-        aliases = createAliases(Collections.singletonList("node3"));
+        aliases = createAliases(List.of("node3"));
         map = allocate(hostProvisioner, aliases);
 
         assertCorrectNumberOfHost(map, 1);
@@ -48,7 +47,7 @@ public class SingleNodeProvisionerTest {
         assertTrue(map.keySet().containsAll(aliases));
 
         // 5 services, 3 host aliases, mapping to 3 host.
-        aliases = createAliases(Collections.singletonList("node4"));
+        aliases = createAliases(List.of("node4"));
         map = allocate(hostProvisioner, aliases);
         assertThat(map.size(), is(3));
         assertCorrectNumberOfHost(map, 1);
diff --git a/config-model/src/test/java/com/yahoo/schema/DocumentGraphValidatorTest.java b/config-model/src/test/java/com/yahoo/schema/DocumentGraphValidatorTest.java
index defc7e59080..88761fc5d3f 100644
--- a/config-model/src/test/java/com/yahoo/schema/DocumentGraphValidatorTest.java
+++ b/config-model/src/test/java/com/yahoo/schema/DocumentGraphValidatorTest.java
@@ -9,7 +9,6 @@ import com.yahoo.schema.document.TemporarySDField;
 import org.junit.jupiter.api.Test;
 
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -142,14 +141,13 @@ public class DocumentGraphValidatorTest {
         Schema campaignSchema = new Schema(name, MockApplicationPackage.createEmpty());
         SDDocumentType document = new SDDocumentType(name);
         campaignSchema.addDocument(document);
-        document.setDocumentReferences(new DocumentReferences(Collections.emptyMap()));
+        document.setDocumentReferences(new DocumentReferences(Map.of()));
         Arrays.stream(parents)
                 .map(Schema::getDocument)
                 .forEach(document::inherit);
         return campaignSchema;
     }
 
-    @SuppressWarnings("deprecation")
     private static void createDocumentReference(Schema from, Schema to, String refFieldName) {
         SDDocumentType fromDocument = from.getDocument();
         SDField refField = new TemporarySDField(fromDocument, refFieldName, NewDocumentReferenceDataType.forDocumentName(to.getName()));
diff --git a/config-model/src/test/java/com/yahoo/schema/DocumentReferenceResolverTest.java b/config-model/src/test/java/com/yahoo/schema/DocumentReferenceResolverTest.java
index e2029df70d6..99946406344 100644
--- a/config-model/src/test/java/com/yahoo/schema/DocumentReferenceResolverTest.java
+++ b/config-model/src/test/java/com/yahoo/schema/DocumentReferenceResolverTest.java
@@ -8,10 +8,9 @@ import com.yahoo.schema.document.SDDocumentType;
 import com.yahoo.schema.document.SDField;
 import org.junit.jupiter.api.Test;
 
+import java.util.List;
 import java.util.Map;
 
-import static java.util.Arrays.asList;
-import static java.util.Collections.singletonList;
 import static org.junit.jupiter.api.Assertions.*;
 
 /**
@@ -40,7 +39,7 @@ public class DocumentReferenceResolverTest {
         fooDocument.addField(irrelevantField);
         fooSchema.addDocument(fooDocument);
 
-        DocumentReferenceResolver resolver = new DocumentReferenceResolver(asList(fooSchema, barSchema));
+        DocumentReferenceResolver resolver = new DocumentReferenceResolver(List.of(fooSchema, barSchema));
         resolver.resolveReferences(fooDocument);
         assertTrue(fooDocument.getDocumentReferences().isPresent());
 
@@ -50,7 +49,6 @@ public class DocumentReferenceResolverTest {
         assertSame(fooRefToBarField, fooReferenceMap.get("bar_ref").referenceField());
     }
 
-    @SuppressWarnings("deprecation")
     @Test
     void throws_user_friendly_exception_if_referenced_document_does_not_exist() {
         Throwable exception = assertThrows(IllegalArgumentException.class, () -> {
@@ -64,7 +62,7 @@ public class DocumentReferenceResolverTest {
             fooDocument.addField(fooRefToBarField);
             fooSchema.addDocument(fooDocument);
 
-            DocumentReferenceResolver resolver = new DocumentReferenceResolver(singletonList(fooSchema));
+            DocumentReferenceResolver resolver = new DocumentReferenceResolver(List.of(fooSchema));
             resolver.resolveReferences(fooDocument);
         });
         assertTrue(exception.getMessage().contains("Invalid document reference 'bar_ref': Could not find document type 'bar'"));
@@ -86,7 +84,7 @@ public class DocumentReferenceResolverTest {
             fooDocument.addField(fooRefToBarField);
             fooSchema.addDocument(fooDocument);
 
-            DocumentReferenceResolver resolver = new DocumentReferenceResolver(asList(fooSchema, barSchema));
+            DocumentReferenceResolver resolver = new DocumentReferenceResolver(List.of(fooSchema, barSchema));
             resolver.resolveReferences(fooDocument);
         });
         assertTrue(exception.getMessage().contains("The field 'bar_ref' is an invalid document reference. The field must be an attribute."));
diff --git a/config-model/src/test/java/com/yahoo/schema/derived/SchemaOrdererTestCase.java b/config-model/src/test/java/com/yahoo/schema/derived/SchemaOrdererTestCase.java
index 593f26eb074..f83892a7a71 100644
--- a/config-model/src/test/java/com/yahoo/schema/derived/SchemaOrdererTestCase.java
+++ b/config-model/src/test/java/com/yahoo/schema/derived/SchemaOrdererTestCase.java
@@ -18,7 +18,6 @@ import java.util.List;
 import java.util.Map;
 import java.util.Objects;
 
-import static java.util.Collections.emptyMap;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
 /**
@@ -63,7 +62,7 @@ public class SchemaOrdererTestCase extends AbstractSchemaTestCase {
     private static Schema createSchema(String name, Map<String, Schema> schemas) {
         Schema schema = new Schema(name, MockApplicationPackage.createEmpty());
         SDDocumentType document = new SDDocumentType(name);
-        document.setDocumentReferences(new DocumentReferences(emptyMap()));
+        document.setDocumentReferences(new DocumentReferences(Map.of()));
         schema.addDocument(document);
         schemas.put(schema.getName(), schema);
         return schema;
@@ -74,7 +73,7 @@ public class SchemaOrdererTestCase extends AbstractSchemaTestCase {
     }
 
     private static void assertOrder(List<String> expectedSearchOrder, List<String> inputNames) {
-        inputNames.sort((a, b) -> a.compareTo(b));
+        inputNames.sort(String::compareTo);
         Map<String, Schema> schemas = createSchemas();
         List<Schema> inputSchemas = inputNames.stream()
                                               .map(schemas::get)
@@ -88,7 +87,6 @@ public class SchemaOrdererTestCase extends AbstractSchemaTestCase {
         assertEquals(expectedSearchOrder, actualSearchOrder);
     }
 
-    @SuppressWarnings("deprecation")
     private static void createDocumentReference(Schema from, Schema to, String refFieldName) {
         SDDocumentType fromDocument = from.getDocument();
         SDField refField = new TemporarySDField(fromDocument, refFieldName, NewDocumentReferenceDataType.forDocumentName(to.getName()));
diff --git a/config-model/src/test/java/com/yahoo/schema/processing/AddDataTypeAndTransformToSummaryOfImportedFieldsTest.java b/config-model/src/test/java/com/yahoo/schema/processing/AddDataTypeAndTransformToSummaryOfImportedFieldsTest.java
index f09a95b89a0..3da6f250853 100644
--- a/config-model/src/test/java/com/yahoo/schema/processing/AddDataTypeAndTransformToSummaryOfImportedFieldsTest.java
+++ b/config-model/src/test/java/com/yahoo/schema/processing/AddDataTypeAndTransformToSummaryOfImportedFieldsTest.java
@@ -19,7 +19,7 @@ import com.yahoo.vespa.documentmodel.SummaryField;
 import com.yahoo.vespa.documentmodel.SummaryTransform;
 import org.junit.jupiter.api.Test;
 
-import java.util.Collections;
+import java.util.Map;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
@@ -63,7 +63,7 @@ public class AddDataTypeAndTransformToSummaryOfImportedFieldsTest {
         SDField targetField = new SDField(doc, "target_field", DataType.INT);
         DocumentReference documentReference = new DocumentReference(new Field("reference_field"), targetSchema);
         ImportedField importedField = new ImportedSimpleField(fieldName, documentReference, targetField);
-        return new ImportedFields(Collections.singletonMap(fieldName, importedField));
+        return new ImportedFields(Map.of(fieldName, importedField));
     }
 
     private static DocumentSummary createDocumentSummary(String fieldName, Schema schema) {
diff --git a/config-model/src/test/java/com/yahoo/schema/processing/RankingExpressionWithTransformerTokensTestCase.java b/config-model/src/test/java/com/yahoo/schema/processing/RankingExpressionWithTransformerTokensTestCase.java
index 9213f97fd9f..6cbd8faf3b0 100644
--- a/config-model/src/test/java/com/yahoo/schema/processing/RankingExpressionWithTransformerTokensTestCase.java
+++ b/config-model/src/test/java/com/yahoo/schema/processing/RankingExpressionWithTransformerTokensTestCase.java
@@ -19,7 +19,7 @@ import com.yahoo.searchlib.rankingexpression.evaluation.TensorValue;
 import com.yahoo.tensor.Tensor;
 import org.junit.jupiter.api.Test;
 
-import java.util.Collections;
+import java.util.Map;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
@@ -94,16 +94,17 @@ public class RankingExpressionWithTransformerTokensTestCase {
         MockApplicationPackage application = (MockApplicationPackage) MockApplicationPackage.createEmpty();
         RankProfileRegistry rankProfileRegistry = new RankProfileRegistry();
         QueryProfileRegistry queryProfileRegistry = application.getQueryProfiles();
-        String sdContent = "search test {\n" +
-                "  document test {}\n" +
-                "  rank-profile my_profile inherits default {}\n" +
-                "}";
+        String sdContent = """
+                search test {
+                  document test {}
+                  rank-profile my_profile inherits default {}
+                }""";
         ApplicationBuilder schemaBuilder = new ApplicationBuilder(application, new MockFileRegistry(), new BaseDeployLogger(), new TestProperties(), rankProfileRegistry, queryProfileRegistry);
         schemaBuilder.addSchema(sdContent);
         schemaBuilder.build(true);
         Schema schema = schemaBuilder.getSchema();
         RankProfile rp = rankProfileRegistry.get(schema, "my_profile");
-        return new RankProfileTransformContext(rp, queryProfileRegistry, Collections.emptyMap(), null, Collections.emptyMap(), Collections.emptyMap());
+        return new RankProfileTransformContext(rp, queryProfileRegistry, Map.of(), null, Map.of(), Map.of());
     }
 
 }
diff --git a/config-model/src/test/java/com/yahoo/schema/processing/ValidateFieldTypesTest.java b/config-model/src/test/java/com/yahoo/schema/processing/ValidateFieldTypesTest.java
index be72d2b12fa..8585a206d77 100644
--- a/config-model/src/test/java/com/yahoo/schema/processing/ValidateFieldTypesTest.java
+++ b/config-model/src/test/java/com/yahoo/schema/processing/ValidateFieldTypesTest.java
@@ -18,7 +18,7 @@ import com.yahoo.vespa.documentmodel.DocumentSummary;
 import com.yahoo.vespa.documentmodel.SummaryField;
 import org.junit.jupiter.api.Test;
 
-import java.util.Collections;
+import java.util.Map;
 
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
@@ -65,7 +65,7 @@ public class ValidateFieldTypesTest {
         SDField targetField = new SDField(targetSchema.getDocument(), "target_field", dataType);
         DocumentReference documentReference = new DocumentReference(new Field("reference_field"), targetSchema);
         ImportedField importedField = new ImportedSimpleField(fieldName, documentReference, targetField);
-        return new ImportedFields(Collections.singletonMap(fieldName, importedField));
+        return new ImportedFields(Map.of(fieldName, importedField));
     }
 
     private static DocumentSummary createDocumentSummary(String fieldName, DataType dataType, Schema schema) {
diff --git a/config-model/src/test/java/com/yahoo/vespa/model/admin/metricsproxy/MetricsConsumersTest.java b/config-model/src/test/java/com/yahoo/vespa/model/admin/metricsproxy/MetricsConsumersTest.java
index 88e1ba7a1a6..94dd0f367a3 100644
--- a/config-model/src/test/java/com/yahoo/vespa/model/admin/metricsproxy/MetricsConsumersTest.java
+++ b/config-model/src/test/java/com/yahoo/vespa/model/admin/metricsproxy/MetricsConsumersTest.java
@@ -8,6 +8,8 @@ import com.yahoo.vespa.model.VespaModel;
 import com.yahoo.vespa.model.admin.monitoring.MetricsConsumer;
 import org.junit.jupiter.api.Test;
 
+import java.util.List;
+
 import static ai.vespa.metrics.set.DefaultMetrics.defaultMetricSet;
 import static ai.vespa.metrics.set.DefaultVespaMetrics.defaultVespaMetricSet;
 import static ai.vespa.metrics.set.NetworkMetrics.networkMetricSet;
@@ -21,7 +23,6 @@ import static com.yahoo.vespa.model.admin.metricsproxy.MetricsProxyModelTester.c
 import static com.yahoo.vespa.model.admin.metricsproxy.MetricsProxyModelTester.getCustomConsumer;
 import static com.yahoo.vespa.model.admin.metricsproxy.MetricsProxyModelTester.getModel;
 import static com.yahoo.vespa.model.admin.metricsproxy.MetricsProxyModelTester.servicesWithAdminOnly;
-import static java.util.Collections.singleton;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertTrue;
@@ -72,7 +73,7 @@ public class MetricsConsumersTest {
     void vespa_consumer_can_be_amended_via_admin_object() {
         VespaModel model = getModel(servicesWithAdminOnly(), hosted);
         var additionalMetric = new Metric("additional-metric");
-        model.getAdmin().setAdditionalDefaultMetrics(new MetricSet("amender-metrics", singleton(additionalMetric)));
+        model.getAdmin().setAdditionalDefaultMetrics(new MetricSet("amender-metrics", List.of(additionalMetric)));
 
         ConsumersConfig config = consumersConfigFromModel(model);
         assertEquals(numMetricsForVespaConsumer + 1, config.consumer(0).metric().size());
diff --git a/config-model/src/test/java/com/yahoo/vespa/model/application/validation/change/search/DocumentTypeChangeValidatorTest.java b/config-model/src/test/java/com/yahoo/vespa/model/application/validation/change/search/DocumentTypeChangeValidatorTest.java
index 44743c4fa3e..0e3d74a6995 100644
--- a/config-model/src/test/java/com/yahoo/vespa/model/application/validation/change/search/DocumentTypeChangeValidatorTest.java
+++ b/config-model/src/test/java/com/yahoo/vespa/model/application/validation/change/search/DocumentTypeChangeValidatorTest.java
@@ -15,9 +15,9 @@ import org.junit.jupiter.api.Test;
 
 import java.time.Instant;
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.List;
 import java.util.Optional;
+import java.util.Set;
 
 import static com.yahoo.vespa.model.application.validation.change.ConfigChangeTestUtils.newRefeedAction;
 import static org.junit.jupiter.api.Assertions.assertEquals;
@@ -210,8 +210,8 @@ public class DocumentTypeChangeValidatorTest {
                 new NewDocumentType.Name("mydoc"),
                 headerfields,
                 new FieldSets(Optional.empty()),
-                Collections.emptySet(),
-                Collections.emptySet());
+                Set.of(),
+                Set.of());
     }
 
 }
diff --git a/config-model/src/test/java/com/yahoo/vespa/model/container/configserver/ConfigserverClusterTest.java b/config-model/src/test/java/com/yahoo/vespa/model/container/configserver/ConfigserverClusterTest.java
index b933d86655e..5e6863360e7 100644
--- a/config-model/src/test/java/com/yahoo/vespa/model/container/configserver/ConfigserverClusterTest.java
+++ b/config-model/src/test/java/com/yahoo/vespa/model/container/configserver/ConfigserverClusterTest.java
@@ -22,11 +22,9 @@ import com.yahoo.vespa.model.container.xml.ConfigServerContainerModelBuilder;
 import org.junit.jupiter.api.Test;
 
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.List;
 import java.util.Optional;
 import java.util.function.Function;
-import java.util.stream.Collectors;
 
 import static org.junit.jupiter.api.Assertions.*;
 
@@ -46,7 +44,7 @@ public class ConfigserverClusterTest {
 
     @Test
     void zookeeperConfig_only_config_servers_set_hosted() {
-        TestOptions testOptions = createTestOptions(Arrays.asList("cfg1", "localhost", "cfg3"), Collections.emptyList());
+        TestOptions testOptions = createTestOptions(Arrays.asList("cfg1", "localhost", "cfg3"), List.of());
         ZookeeperServerConfig config = getConfig(ZookeeperServerConfig.class, testOptions);
         assertZookeeperServerProperty(config.server(), ZookeeperServerConfig.Server::hostname, "cfg1", "localhost", "cfg3");
         assertZookeeperServerProperty(config.server(), ZookeeperServerConfig.Server::id, 0, 1, 2);
@@ -57,7 +55,7 @@ public class ConfigserverClusterTest {
 
     @Test
     void zookeeperConfig_with_config_servers_and_zk_ids_hosted() {
-        TestOptions testOptions = createTestOptions(Arrays.asList("cfg1", "localhost", "cfg3"), Arrays.asList(4, 2, 3));
+        TestOptions testOptions = createTestOptions(Arrays.asList("cfg1", "localhost", "cfg3"), List.of(4, 2, 3));
         ZookeeperServerConfig config = getConfig(ZookeeperServerConfig.class, testOptions);
         assertZookeeperServerProperty(config.server(), ZookeeperServerConfig.Server::hostname, "cfg1", "localhost", "cfg3");
         assertZookeeperServerProperty(config.server(), ZookeeperServerConfig.Server::id, 4, 2, 3);
@@ -80,7 +78,7 @@ public class ConfigserverClusterTest {
     @Test
     void zookeeperConfig_uneven_number_of_config_servers_and_zk_ids() {
         assertThrows(IllegalArgumentException.class, () -> {
-            TestOptions testOptions = createTestOptions(Arrays.asList("cfg1", "localhost", "cfg3"), Collections.singletonList(1));
+            TestOptions testOptions = createTestOptions(Arrays.asList("cfg1", "localhost", "cfg3"), List.of(1));
             getConfig(ZookeeperServerConfig.class, testOptions);
         });
     }
@@ -88,7 +86,7 @@ public class ConfigserverClusterTest {
     @Test
     void zookeeperConfig_negative_zk_id() {
         assertThrows(IllegalArgumentException.class, () -> {
-            TestOptions testOptions = createTestOptions(Arrays.asList("cfg1", "localhost", "cfg3"), Arrays.asList(1, 2, -1));
+            TestOptions testOptions = createTestOptions(Arrays.asList("cfg1", "localhost", "cfg3"), List.of(1, 2, -1));
             getConfig(ZookeeperServerConfig.class, testOptions);
         });
     }
@@ -169,7 +167,7 @@ public class ConfigserverClusterTest {
     }
 
     private static <CONFIGTYPE extends ConfigInstance> CONFIGTYPE getConfig(Class<CONFIGTYPE> clazz) {
-        return getConfig(clazz, createTestOptions(Collections.emptyList(), Collections.emptyList()));
+        return getConfig(clazz, createTestOptions(List.of(), List.of()));
     }
 
     private static <CONFIGTYPE extends ConfigInstance> CONFIGTYPE getConfig(Class<CONFIGTYPE> clazz, TestOptions testOptions) {
diff --git a/config-model/src/test/java/com/yahoo/vespa/model/container/http/BlockFeedGlobalEndpointsFilterTest.java b/config-model/src/test/java/com/yahoo/vespa/model/container/http/BlockFeedGlobalEndpointsFilterTest.java
index 73c4075a182..3345f935e1d 100644
--- a/config-model/src/test/java/com/yahoo/vespa/model/container/http/BlockFeedGlobalEndpointsFilterTest.java
+++ b/config-model/src/test/java/com/yahoo/vespa/model/container/http/BlockFeedGlobalEndpointsFilterTest.java
@@ -7,7 +7,6 @@ import com.yahoo.config.model.api.ContainerEndpoint;
 import com.yahoo.vespa.config.jdisc.http.filter.RuleBasedFilterConfig;
 import org.junit.jupiter.api.Test;
 
-import java.util.Collections;
 import java.util.List;
 import java.util.Set;
 
@@ -29,7 +28,7 @@ public class BlockFeedGlobalEndpointsFilterTest {
 
     @Test
     void does_not_setup_blocking_rule_when_endpoints_empty() {
-        var filter = new BlockFeedGlobalEndpointsFilter(Collections.emptySet(), true);
+        var filter = new BlockFeedGlobalEndpointsFilter(Set.of(), true);
         var config = getConfig(filter);
         assertEquals(0, config.rule().size());
     }
diff --git a/config-model/src/test/java/com/yahoo/vespa/model/container/xml/ContainerModelBuilderTestBase.java b/config-model/src/test/java/com/yahoo/vespa/model/container/xml/ContainerModelBuilderTestBase.java
index a066308b426..a832c54021f 100644
--- a/config-model/src/test/java/com/yahoo/vespa/model/container/xml/ContainerModelBuilderTestBase.java
+++ b/config-model/src/test/java/com/yahoo/vespa/model/container/xml/ContainerModelBuilderTestBase.java
@@ -19,8 +19,8 @@ import org.junit.jupiter.api.BeforeEach;
 import org.w3c.dom.Element;
 
 import java.util.ArrayList;
-import java.util.Collections;
 import java.util.List;
+import java.util.Map;
 import java.util.logging.Level;
 
 import static org.junit.jupiter.api.Assertions.assertNotNull;
@@ -88,7 +88,7 @@ public abstract class ContainerModelBuilderTestBase {
     private static void generateDefaultSearchChains(ContainerCluster<?> cluster) {
         ContainerSearch search = cluster.getSearch();
         if (search != null)
-            search.initializeSearchChains(Collections.emptyMap());
+            search.initializeSearchChains(Map.of());
     }
 
     protected ComponentsConfig componentsConfig() {
diff --git a/config-model/src/test/java/com/yahoo/vespa/model/content/ContentClusterTest.java b/config-model/src/test/java/com/yahoo/vespa/model/content/ContentClusterTest.java
index 1ba5bebea7e..4cf950e319d 100644
--- a/config-model/src/test/java/com/yahoo/vespa/model/content/ContentClusterTest.java
+++ b/config-model/src/test/java/com/yahoo/vespa/model/content/ContentClusterTest.java
@@ -22,7 +22,6 @@ import com.yahoo.vespa.config.content.AllClustersBucketSpacesConfig;
 import com.yahoo.vespa.config.content.DistributionConfig;
 import com.yahoo.vespa.config.content.FleetcontrollerConfig;
 import com.yahoo.vespa.config.content.StorDistributionConfig;
-import com.yahoo.vespa.config.content.StorFilestorConfig;
 import com.yahoo.vespa.config.content.core.StorDistributormanagerConfig;
 import com.yahoo.vespa.config.content.core.StorServerConfig;
 import com.yahoo.vespa.config.search.DispatchConfig;
@@ -44,7 +43,6 @@ import com.yahoo.yolean.Exceptions;
 import org.junit.jupiter.api.Test;
 
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
@@ -947,8 +945,8 @@ public class ContentClusterTest extends ContentBaseTest {
                 .properties(props);
         MockRoot root = flavor.isPresent() ?
                 ContentClusterUtils.createMockRoot(new SingleNodeProvisioner(flavor.get()),
-                        Collections.emptyList(), deployStateBuilder) :
-                ContentClusterUtils.createMockRoot(Collections.emptyList(), deployStateBuilder);
+                        List.of(), deployStateBuilder) :
+                ContentClusterUtils.createMockRoot(List.of(), deployStateBuilder);
         ContentCluster cluster = ContentClusterUtils.createCluster(clusterXml, root);
         root.freezeModelTopology();
         cluster.validate();
@@ -1104,8 +1102,8 @@ public class ContentClusterTest extends ContentBaseTest {
 
         assertEquals(2, config.cluster().size());
 
-        assertClusterHasBucketSpaceMappings(config, "foo_c", Arrays.asList("bunnies", "hares"), Collections.emptyList());
-        assertClusterHasBucketSpaceMappings(config, "bar_c", Collections.emptyList(), Collections.singletonList("rabbits"));
+        assertClusterHasBucketSpaceMappings(config, "foo_c", Arrays.asList("bunnies", "hares"), List.of());
+        assertClusterHasBucketSpaceMappings(config, "bar_c", List.of(), List.of("rabbits"));
     }
 
     @Test
diff --git a/config-model/src/test/java/com/yahoo/vespa/model/content/GlobalDistributionValidatorTest.java b/config-model/src/test/java/com/yahoo/vespa/model/content/GlobalDistributionValidatorTest.java
index 6066a27cff5..e671a47b36c 100644
--- a/config-model/src/test/java/com/yahoo/vespa/model/content/GlobalDistributionValidatorTest.java
+++ b/config-model/src/test/java/com/yahoo/vespa/model/content/GlobalDistributionValidatorTest.java
@@ -11,8 +11,6 @@ import java.util.Map;
 import java.util.Set;
 import java.util.stream.Stream;
 
-import static java.util.Collections.emptyMap;
-import static java.util.Collections.emptySet;
 import static java.util.stream.Collectors.toSet;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.fail;
@@ -25,7 +23,7 @@ public class GlobalDistributionValidatorTest {
     @Test
     void validation_succeeds_on_no_documents() {
         new GlobalDistributionValidator()
-                .validate(emptyMap(), emptySet());
+                .validate(Map.of(), Set.of());
     }
 
     @Test
diff --git a/config-model/src/test/java/com/yahoo/vespa/model/content/ReservedDocumentTypeNameValidatorTest.java b/config-model/src/test/java/com/yahoo/vespa/model/content/ReservedDocumentTypeNameValidatorTest.java
index a6fa0334668..68856fe3488 100644
--- a/config-model/src/test/java/com/yahoo/vespa/model/content/ReservedDocumentTypeNameValidatorTest.java
+++ b/config-model/src/test/java/com/yahoo/vespa/model/content/ReservedDocumentTypeNameValidatorTest.java
@@ -5,7 +5,6 @@ import com.yahoo.documentmodel.NewDocumentType;
 import org.junit.jupiter.api.Test;
 
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.List;
 import java.util.Map;
 import java.util.TreeMap;
@@ -40,7 +39,7 @@ public class ReservedDocumentTypeNameValidatorTest {
     @Test
     void exception_is_not_thrown_on_unreserved_name() {
         ReservedDocumentTypeNameValidator validator = new ReservedDocumentTypeNameValidator();
-        validator.validate(asDocTypeMapping(Collections.singletonList("foo")));
+        validator.validate(asDocTypeMapping(List.of("foo")));
     }
 
     @Test
diff --git a/config-model/src/test/java/com/yahoo/vespa/model/content/TopologicalDocumentTypeSorterTest.java b/config-model/src/test/java/com/yahoo/vespa/model/content/TopologicalDocumentTypeSorterTest.java
index c5a645bd863..3de46f00db5 100644
--- a/config-model/src/test/java/com/yahoo/vespa/model/content/TopologicalDocumentTypeSorterTest.java
+++ b/config-model/src/test/java/com/yahoo/vespa/model/content/TopologicalDocumentTypeSorterTest.java
@@ -6,7 +6,6 @@ import org.junit.jupiter.api.Test;
 
 import java.util.ArrayList;
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.List;
 import java.util.Set;
 import java.util.stream.Collectors;
@@ -20,24 +19,24 @@ public class TopologicalDocumentTypeSorterTest {
 
     @Test
     void require_that_types_without_references_are_returned_in_input_order() {
-        assertOrder(Arrays.asList("a"), new DocumentTypesBuilder().add("a"));
-        assertOrder(Arrays.asList("a", "c", "b"),
+        assertOrder(List.of("a"), new DocumentTypesBuilder().add("a"));
+        assertOrder(List.of("a", "c", "b"),
                 new DocumentTypesBuilder().add("a").add("c").add("b"));
     }
 
     @Test
     void require_that_types_with_references_are_sorted_in_topological_order() {
         assertOrder(Arrays.asList("b", "a"), new DocumentTypesBuilder()
-                .add("a", Arrays.asList("b"))
+                .add("a", List.of("b"))
                 .add("b"));
         assertOrder(Arrays.asList("c", "b", "a"), new DocumentTypesBuilder()
                 .add("a", Arrays.asList("b", "c"))
-                .add("b", Arrays.asList("c"))
+                .add("b", List.of("c"))
                 .add("c"));
         assertOrder(Arrays.asList("b", "a", "d", "c"), new DocumentTypesBuilder()
-                .add("a", Arrays.asList("b"))
+                .add("a", List.of("b"))
                 .add("b")
-                .add("c", Arrays.asList("d"))
+                .add("c", List.of("d"))
                 .add("d"));
     }
 
@@ -52,7 +51,7 @@ public class TopologicalDocumentTypeSorterTest {
         private final List<NewDocumentType> result = new ArrayList<>();
 
         public DocumentTypesBuilder add(String docTypeName) {
-            return add(docTypeName, Collections.emptyList());
+            return add(docTypeName, List.of());
         }
 
         public DocumentTypesBuilder add(String docTypeName, List<String> docTypeNameReferences) {
diff --git a/config-model/src/test/java/com/yahoo/vespa/model/content/utils/ContentClusterUtils.java b/config-model/src/test/java/com/yahoo/vespa/model/content/utils/ContentClusterUtils.java
index a8c67ebf0a3..360ad19b710 100644
--- a/config-model/src/test/java/com/yahoo/vespa/model/content/utils/ContentClusterUtils.java
+++ b/config-model/src/test/java/com/yahoo/vespa/model/content/utils/ContentClusterUtils.java
@@ -16,7 +16,6 @@ import com.yahoo.vespa.model.admin.monitoring.builder.Metrics;
 import com.yahoo.vespa.model.content.cluster.ContentCluster;
 import org.w3c.dom.Document;
 
-import java.util.Collections;
 import java.util.List;
 import java.util.Optional;
 
@@ -67,7 +66,7 @@ public class ContentClusterUtils {
         ConfigModelContext context = ConfigModelContext.create(applicationType, root.getDeployState(),
                                                                null,null, root, null);
 
-        return new ContentCluster.Builder(admin).build(Collections.emptyList(), context, doc.getDocumentElement());
+        return new ContentCluster.Builder(admin).build(List.of(), context, doc.getDocumentElement());
     }
 
     public static ContentCluster createCluster(String clusterXml, List<String> schemas, DeployState.Builder deployStateBuilder) throws Exception {