Reverted StrictMapAppenderConstructor constructor back to public

Issue: SPR-13504
(cherry picked from commit 627393a)

Author: jhoeller

spring-beans/src/main/java/org/springframework/beans/factory/config/YamlProcessor.java

@@ -42,7 +42,7 @@
 import org.springframework.util.StringUtils;
 
 /**
- * Base class for Yaml factories.
+ * Base class for YAML factories.
  *
  * @author Dave Syer
  * @since 4.1
@@ -65,7 +65,6 @@ public abstract class YamlProcessor {
 	 * some of the documents in a YAML resource. In YAML documents are
 	 * separated by <code>---<code> lines, and each document is converted
 	 * to properties before the match is made. E.g.
-	 *
 	 * <pre class="code">
 	 * environment: dev
 	 * url: http://dev.bar.com
@@ -75,11 +74,9 @@ public abstract class YamlProcessor {
 	 * url:http://foo.bar.com
 	 * name: My Cool App
 	 * </pre>
-	 *
 	 * when mapped with
 	 * <code>documentMatchers = YamlProcessor.mapMatcher({"environment": "prod"})</code>
 	 * would end up as
-	 *
 	 * <pre class="code">
 	 * environment=prod
 	 * url=http://foo.bar.com
@@ -103,9 +100,9 @@ public void setMatchDefault(boolean matchDefault) {
 	}
 
 	/**
-	 * Method to use for resolving resources. Each resource will be converted to a Map, so
-	 * this property is used to decide which map entries to keep in the final output from
-	 * this factory.
+	 * Method to use for resolving resources. Each resource will be converted to a Map,
+	 * so this property is used to decide which map entries to keep in the final output
+	 * from this factory.
 	 * @param resolutionMethod the resolution method to set (defaults to
 	 * {@link ResolutionMethod#OVERRIDE}).
 	 */
@@ -127,9 +124,9 @@ public void setResources(Resource... resources) {
 	 * Provide an opportunity for subclasses to process the Yaml parsed from the supplied
 	 * resources. Each resource is parsed in turn and the documents inside checked against
 	 * the {@link #setDocumentMatchers(DocumentMatcher...) matchers}. If a document
-	 * matches it is passed into the callback, along with its representation as
-	 * Properties. Depending on the {@link #setResolutionMethod(ResolutionMethod)} not all
-	 * of the documents will be parsed.
+	 * matches it is passed into the callback, along with its representation as Properties.
+	 * Depending on the {@link #setResolutionMethod(ResolutionMethod)} not all of the
+	 * documents will be parsed.
 	 * @param callback a callback to delegate to once matching documents are found
 	 * @see #createYaml()
 	 */
@@ -393,6 +390,11 @@ public enum ResolutionMethod {
 	 */
 	protected static class StrictMapAppenderConstructor extends Constructor {
 
+		// Declared as public for use in subclasses
+		public StrictMapAppenderConstructor() {
+			super();
+		}
+
 		@Override
 		protected Map<Object, Object> constructMapping(MappingNode node) {
 			try {
@@ -421,7 +423,6 @@ public Set<Entry<Object, Object>> entrySet() {
 				}
 			};
 		}
-
 	}
 
 }