[java] Deprecate base class ExcessiveLengthRule

docs/pages/release_notes.md

@@ -27,6 +27,15 @@ This is a {{ site.pmd.release_type }} release.
 
 ### API Changes
 
+#### Deprecated APIs
+
+##### Internal API
+
+Those APIs are not intended to be used by clients, and will be hidden or removed with PMD 7.0.0. You can identify
+them with the `@InternalApi` annotation. You'll also get a deprecation warning.
+
+* {% jdoc java::lang.java.rule.design.ExcessiveLengthRule %} (Java)
+
 ### External Contributions
 
 {% endtocmaker %}

pmd-java/src/main/java/net/sourceforge/pmd/lang/java/rule/design/ExcessiveLengthRule.java

@@ -4,6 +4,7 @@
 
 package net.sourceforge.pmd.lang.java.rule.design;
 
+import net.sourceforge.pmd.annotation.InternalApi;
 import net.sourceforge.pmd.lang.java.ast.JavaNode;
 import net.sourceforge.pmd.lang.java.rule.AbstractStatisticalJavaRule;
 import net.sourceforge.pmd.stat.DataPoint;
@@ -19,6 +20,7 @@ import net.sourceforge.pmd.stat.DataPoint;
  * @deprecated This base class is not needed anymore and will be removed with PMD 7.
  */
 @Deprecated
+@InternalApi
 public class ExcessiveLengthRule extends AbstractStatisticalJavaRule {
     private Class<?> nodeClass;