Use constant fields for Reactive Wrapper Converters guards.

Enables reachability analysis. Previously, the presence checks were using method invocations and the AOT processing isn't following the methods.

Original Pull Request: #2624

Author: mp911de

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

@@ -64,28 +64,34 @@ public abstract class ReactiveWrapperConverters {
 	private static final List<ReactiveTypeWrapper<?>> REACTIVE_WRAPPERS = new ArrayList<>();
 	private static final GenericConversionService GENERIC_CONVERSION_SERVICE = new GenericConversionService();
 
+	private static final boolean RXJAVA3_PRESENT = ReactiveWrappers.isAvailable(ReactiveLibrary.RXJAVA3);
+	private static final boolean REACTOR_PRESENT = ReactiveWrappers.isAvailable(ReactiveLibrary.PROJECT_REACTOR);
+	private static final boolean KOTLIN_COROUTNES_PRESENT = ReactiveWrappers
+			.isAvailable(ReactiveLibrary.KOTLIN_COROUTINES);
+	private static final boolean MUTINY_PRESENT = ReactiveWrappers.isAvailable(ReactiveLibrary.MUTINY);
+
 	static {
 
-		if (ReactiveWrappers.isAvailable(ReactiveLibrary.RXJAVA3)) {
+		if (RXJAVA3_PRESENT) {
 
 			REACTIVE_WRAPPERS.add(RxJava3SingleWrapper.INSTANCE);
 			REACTIVE_WRAPPERS.add(RxJava3MaybeWrapper.INSTANCE);
 			REACTIVE_WRAPPERS.add(RxJava3ObservableWrapper.INSTANCE);
 			REACTIVE_WRAPPERS.add(RxJava3FlowableWrapper.INSTANCE);
 		}
 
-		if (ReactiveWrappers.isAvailable(ReactiveLibrary.PROJECT_REACTOR)) {
+		if (REACTOR_PRESENT) {
 
 			REACTIVE_WRAPPERS.add(FluxWrapper.INSTANCE);
 			REACTIVE_WRAPPERS.add(MonoWrapper.INSTANCE);
 			REACTIVE_WRAPPERS.add(PublisherWrapper.INSTANCE);
 		}
 
-		if (ReactiveWrappers.isAvailable(ReactiveLibrary.KOTLIN_COROUTINES)) {
+		if (KOTLIN_COROUTNES_PRESENT) {
 			REACTIVE_WRAPPERS.add(FlowWrapper.INSTANCE);
 		}
 
-		if (ReactiveWrappers.isAvailable(ReactiveLibrary.MUTINY)) {
+		if (MUTINY_PRESENT) {
 			REACTIVE_WRAPPERS.add(UniWrapper.INSTANCE);
 			REACTIVE_WRAPPERS.add(MultiWrapper.INSTANCE);
 		}
@@ -104,12 +110,12 @@ private static ConversionService registerConvertersIn(ConfigurableConversionServ
 
 		Assert.notNull(conversionService, "ConversionService must not be null");
 
-		if (ReactiveWrappers.isAvailable(ReactiveLibrary.PROJECT_REACTOR)) {
+		if (REACTOR_PRESENT) {
 
 			conversionService.addConverter(PublisherToMonoConverter.INSTANCE);
 			conversionService.addConverter(PublisherToFluxConverter.INSTANCE);
 
-			if (ReactiveWrappers.isAvailable(ReactiveLibrary.KOTLIN_COROUTINES)) {
+			if (KOTLIN_COROUTNES_PRESENT) {
 				conversionService.addConverter(PublisherToFlowConverter.INSTANCE);
 			}
 
@@ -439,7 +445,6 @@ public io.smallrye.mutiny.Multi<?> map(Object wrapper, Function<Object, Object>
 		}
 	}
 
-
 	// -------------------------------------------------------------------------
 	// ReactiveStreams converters
 	// -------------------------------------------------------------------------