Make intermediate classes in type hierarchy of public class public

See gh-12590

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/condition/AbstractNestedCondition.java

@@ -40,8 +40,9 @@ import org.springframework.util.MultiValueMap;
  * Abstract base class for nested conditions.
  *
  * @author Phillip Webb
+ * @since 2.0.1
  */
-abstract class AbstractNestedCondition extends SpringBootCondition
+public abstract class AbstractNestedCondition extends SpringBootCondition
 		implements ConfigurationCondition {
 
 	private final ConfigurationPhase configurationPhase;

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/freemarker/FreeMarkerNonWebConfiguration.java

@@ -30,9 +30,9 @@ import org.springframework.ui.freemarker.FreeMarkerConfigurationFactoryBean;
  */
 @Configuration
 @ConditionalOnNotWebApplication
-public class FreeMarkerNonWebConfiguration extends AbstractFreeMarkerConfiguration {
+class FreeMarkerNonWebConfiguration extends AbstractFreeMarkerConfiguration {
 
-	public FreeMarkerNonWebConfiguration(FreeMarkerProperties properties) {
+	FreeMarkerNonWebConfiguration(FreeMarkerProperties properties) {
 		super(properties);
 	}
 

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/json/AbstractJsonParser.java

@@ -28,8 +28,9 @@ import org.springframework.util.ReflectionUtils;
  *
  * @author Anton Telechev
  * @author Phillip Webb
+ * @since 2.0.1
  */
-abstract class AbstractJsonParser implements JsonParser {
+public abstract class AbstractJsonParser implements JsonParser {
 
 	protected final Map<String, Object> parseMap(String json,
 			Function<String, Map<String, Object>> parser) {

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/servlet/AbstractFilterRegistrationBean.java

@@ -41,8 +41,9 @@ import org.springframework.util.StringUtils;
  *
  * @param <T> the type of {@link Filter} to register
  * @author Phillip Webb
+ * @since 2.0.1
  */
-abstract class AbstractFilterRegistrationBean<T extends Filter>
+public abstract class AbstractFilterRegistrationBean<T extends Filter>
 		extends DynamicRegistrationBean<Dynamic> {
 
 	/**