Initialize maps & sets with size where possible.

Author: christophstrobl

src/main/java/org/springframework/data/convert/SimplePropertyValueConverterRegistry.java

@@ -32,12 +32,14 @@
 public class SimplePropertyValueConverterRegistry<P extends PersistentProperty<P>>
 		implements ValueConverterRegistry<P> {
 
-	private final Map<Key, PropertyValueConverter<?, ?, ? extends ValueConversionContext<P>>> converterRegistrationMap = new LinkedHashMap<>();
+	private final Map<Key, PropertyValueConverter<?, ?, ? extends ValueConversionContext<P>>> converterRegistrationMap;
 
-	public SimplePropertyValueConverterRegistry() {}
+	public SimplePropertyValueConverterRegistry() {
+		this.converterRegistrationMap = new LinkedHashMap<>();
+	}
 
 	SimplePropertyValueConverterRegistry(SimplePropertyValueConverterRegistry<P> source) {
-		this.converterRegistrationMap.putAll(source.converterRegistrationMap);
+		this.converterRegistrationMap = new LinkedHashMap<>(source.converterRegistrationMap);
 	}
 
 	@Override

src/main/java/org/springframework/data/domain/ExampleMatcher.java

@@ -775,12 +775,14 @@ protected boolean canEqual(final Object other) {
 	 */
 	class PropertySpecifiers {
 
-		private final Map<String, PropertySpecifier> propertySpecifiers = new LinkedHashMap<>();
+		private final Map<String, PropertySpecifier> propertySpecifiers;
 
-		PropertySpecifiers() {}
+		PropertySpecifiers() {
+			this. propertySpecifiers = new LinkedHashMap<>();
+		}
 
 		PropertySpecifiers(PropertySpecifiers propertySpecifiers) {
-			this.propertySpecifiers.putAll(propertySpecifiers.propertySpecifiers);
+			this.propertySpecifiers = new LinkedHashMap<>(propertySpecifiers.propertySpecifiers);
 		}
 
 		public void add(PropertySpecifier specifier) {

src/main/java/org/springframework/data/geo/format/DistanceFormatter.java

@@ -47,7 +47,7 @@ public enum DistanceFormatter implements Converter<String, Distance>, Formatter<
 
 	static {
 
-		Map<String, Metric> metrics = new LinkedHashMap<>();
+		Map<String, Metric> metrics = new LinkedHashMap<>(Metrics.values().length);
 
 		for (Metric metric : Metrics.values()) {
 			metrics.put(metric.getAbbreviation(), metric);

src/main/java/org/springframework/data/mapping/context/AbstractMappingContext.java

@@ -461,7 +461,7 @@ private E doAddPersistentEntity(TypeInformation<?> typeInformation) {
 
 			if (shouldCreateProperties(userTypeInformation)) {
 				PropertyDescriptor[] pds = BeanUtils.getPropertyDescriptors(type);
-				Map<String, PropertyDescriptor> descriptors = new HashMap<>();
+				Map<String, PropertyDescriptor> descriptors = new HashMap<>(pds.length);
 
 				for (PropertyDescriptor descriptor : pds) {
 					descriptors.put(descriptor.getName(), descriptor);

src/main/java/org/springframework/data/mapping/model/ClassGeneratingPropertyAccessorFactory.java

@@ -1395,7 +1395,7 @@ private static int getInvokeOp(Method method, boolean interfaceDefinition) {
 	private static Map<String, PropertyStackAddress> createPropertyStackMap(
 			List<PersistentProperty<?>> persistentProperties) {
 
-		Map<String, PropertyStackAddress> stackmap = new HashMap<>();
+		Map<String, PropertyStackAddress> stackmap = new HashMap<>(persistentProperties.size());
 
 		for (PersistentProperty<?> property : persistentProperties) {
 			stackmap.put(property.getName(), new PropertyStackAddress(new Label(), property.getName().hashCode()));

src/main/java/org/springframework/data/projection/SpelEvaluatingMethodInterceptor.java

@@ -107,9 +107,10 @@ public SpelEvaluatingMethodInterceptor(MethodInterceptor delegate, Object target
 	private static Map<Integer, Expression> potentiallyCreateExpressionsForMethodsOnTargetInterface(
 			ExpressionParser parser, Class<?> targetInterface) {
 
-		Map<Integer, Expression> expressions = new HashMap<>();
+		Method[] methods = targetInterface.getMethods();
+		Map<Integer, Expression> expressions = new HashMap<>(methods.length);
 
-		for (Method method : targetInterface.getMethods()) {
+		for (Method method : methods) {
 
 			Value value = AnnotationUtils.findAnnotation(method, Value.class);
 			if (value == null) {

src/main/java/org/springframework/data/repository/core/support/QueryExecutorMethodInterceptor.java

@@ -92,9 +92,10 @@ public QueryExecutorMethodInterceptor(RepositoryInformation repositoryInformatio
 	private Map<Method, RepositoryQuery> mapMethodsToQuery(RepositoryInformation repositoryInformation,
 			QueryLookupStrategy lookupStrategy, ProjectionFactory projectionFactory) {
 
-		Map<Method, RepositoryQuery> result = new HashMap<>();
+		List<Method> queryMethods = repositoryInformation.getQueryMethods().toList();
+		Map<Method, RepositoryQuery> result = new HashMap<>(queryMethods.size());
 
-		for (Method method : repositoryInformation.getQueryMethods()) {
+		for (Method method : queryMethods) {
 
 			Pair<Method, RepositoryQuery> pair = lookupQuery(method, repositoryInformation, lookupStrategy,
 					projectionFactory);

src/main/java/org/springframework/data/repository/core/support/RepositoryFactorySupport.java

@@ -725,7 +725,7 @@ public String toString() {
 	 */
 	static class RepositoryValidator {
 
-		static Map<Class<?>, String> WELL_KNOWN_EXECUTORS = new HashMap<>();
+		static Map<Class<?>, String> WELL_KNOWN_EXECUTORS = new HashMap<>(4, 1f);
 
 		static {
 

src/main/java/org/springframework/data/repository/query/ExtensionAwareQueryMethodEvaluationContextProvider.java

@@ -100,7 +100,7 @@ public ExtensionAwareQueryMethodEvaluationContextProvider(List<? extends Evaluat
 	 */
 	static Map<String, Object> collectVariables(Parameters<?, ?> parameters, Object[] arguments) {
 
-		Map<String, Object> variables = new HashMap<>();
+		Map<String, Object> variables = new HashMap<>(parameters.getNumberOfParameters());
 
 		parameters.stream()//
 				.filter(Parameter::isSpecialParameter)//

src/main/java/org/springframework/data/repository/util/QueryExecutionConverters.java

@@ -78,11 +78,11 @@ public abstract class QueryExecutionConverters {
 	private static final boolean VAVR_PRESENT = ClassUtils.isPresent("io.vavr.control.Try",
 			QueryExecutionConverters.class.getClassLoader());
 
-	private static final Set<WrapperType> WRAPPER_TYPES = new HashSet<>();
-	private static final Set<WrapperType> UNWRAPPER_TYPES = new HashSet<WrapperType>();
+	private static final Set<WrapperType> WRAPPER_TYPES = new HashSet<>(10, 1f);
+	private static final Set<WrapperType> UNWRAPPER_TYPES = new HashSet<WrapperType>(10, 1f);
 	private static final Set<Function<Object, Object>> UNWRAPPERS = new HashSet<>();
 	private static final Set<Class<?>> ALLOWED_PAGEABLE_TYPES = new HashSet<>();
-	private static final Map<Class<?>, ExecutionAdapter> EXECUTION_ADAPTER = new HashMap<>();
+	private static final Map<Class<?>, ExecutionAdapter> EXECUTION_ADAPTER = new HashMap<>(3, 1f);
 	private static final Map<Class<?>, Boolean> supportsCache = new ConcurrentHashMap<>();
 	private static final TypeInformation<Void> VOID_INFORMATION = TypeInformation.of(Void.class);
 

src/main/java/org/springframework/data/util/KotlinBeanInfoFactory.java

@@ -29,6 +29,7 @@
 import java.beans.SimpleBeanInfo;
 import java.lang.reflect.Method;
 import java.util.Arrays;
+import java.util.Collection;
 import java.util.LinkedHashSet;
 import java.util.Set;
 
@@ -59,9 +60,10 @@ public BeanInfo getBeanInfo(Class<?> beanClass) throws IntrospectionException {
 		}
 
 		KClass<?> kotlinClass = JvmClassMappingKt.getKotlinClass(beanClass);
-		Set<PropertyDescriptor> pds = new LinkedHashSet<>();
+		Collection<KCallable<?>> members = kotlinClass.getMembers();
+		Set<PropertyDescriptor> pds = new LinkedHashSet<>(members.size());
 
-		for (KCallable<?> member : kotlinClass.getMembers()) {
+		for (KCallable<?> member : members) {
 
 			if (member instanceof KProperty<?> property) {
 

src/main/java/org/springframework/data/util/TypeCollector.java

@@ -242,7 +242,7 @@ private List<Class<?>> collect() {
 
 	static class InspectionCache {
 
-		private final Map<String, ResolvableType> mutableCache = new LinkedHashMap<>();
+		private final Map<String, ResolvableType> mutableCache = new HashMap<>();
 
 		public void add(ResolvableType resolvableType) {
 			mutableCache.put(resolvableType.toString(), resolvableType);