Consistently use class literals for primitive types

To improve consistency and avoid confusion regarding primitive types
and their wrapper types, this commit ensures that we always use class
literals for primitive types.

For example, instead of using the `Void.TYPE` constant, we now
consistently use `void.class`.

spring-context/src/test/java/org/springframework/aop/framework/ProxyFactoryBeanTests.java

@@ -698,7 +698,7 @@ class ProxyFactoryBeanTests {
 			setPointcut(new DynamicMethodMatcherPointcut() {
 				@Override
 				public boolean matches(Method m, @Nullable Class<?> targetClass, Object... args) {
-					return m.getReturnType() == Void.TYPE;
+					return m.getReturnType() == void.class;
 				}
 			});
 		}