Cache hasUnresolvableGenerics result for repeated checks

Closes gh-30713

(cherry picked from commit 93218a0)

Author: jhoeller

spring-core/src/main/java/org/springframework/core/ResolvableType.java

@@ -133,6 +133,9 @@ public class ResolvableType implements Serializable {
 	@Nullable
 	private volatile ResolvableType[] generics;
 
+	@Nullable
+	private volatile Boolean unresolvableGenerics;
+
 
 	/**
 	 * Private constructor used to create a new {@link ResolvableType} for cache key purposes,
@@ -545,6 +548,15 @@ public boolean hasUnresolvableGenerics() {
 		if (this == NONE) {
 			return false;
 		}
+		Boolean unresolvableGenerics = this.unresolvableGenerics;
+		if (unresolvableGenerics == null) {
+			unresolvableGenerics = determineUnresolvableGenerics();
+			this.unresolvableGenerics = unresolvableGenerics;
+		}
+		return unresolvableGenerics;
+	}
+
+	private boolean determineUnresolvableGenerics() {
 		ResolvableType[] generics = getGenerics();
 		for (ResolvableType generic : generics) {
 			if (generic.isUnresolvableTypeVariable() || generic.isWildcardWithoutBounds()) {