Do not reduce visibility of logger field in abstract class

Author: timtebeek

src/main/java/org/openrewrite/java/logging/ChangeLoggersToPrivate.java

@@ -34,6 +34,7 @@
 
 import static java.util.Collections.emptyList;
 import static java.util.stream.Collectors.toSet;
+import static org.openrewrite.java.tree.J.Modifier.Type.Abstract;
 
 @EqualsAndHashCode(callSuper = false)
 @Value
@@ -76,7 +77,8 @@ public J.VariableDeclarations visitVariableDeclarations(J.VariableDeclarations m
                 }
 
                 J.ClassDeclaration classDeclaration = parent.getValue();
-                if (classDeclaration.getKind() == J.ClassDeclaration.Kind.Type.Interface) {
+                if (classDeclaration.getKind() == J.ClassDeclaration.Kind.Type.Interface ||
+                        classDeclaration.hasModifier(Abstract)) {
                     return mv;
                 }
 

src/test/java/org/openrewrite/java/logging/ChangeLoggersToPrivateTest.java

@@ -175,6 +175,23 @@ interface Constants {
         );
     }
 
+    @Test
+    void loggerInAbstractClassShouldNotChange() {
+        rewriteRun(
+          //language=java
+          java(
+            """
+              import org.slf4j.Logger;
+              import org.slf4j.LoggerFactory;
+
+              abstract class Constants {
+                  Logger logger = LoggerFactory.getLogger(Constants.class);
+              }
+              """
+          )
+        );
+    }
+
     @Test
     void localVariableLoggerShouldNotChange() {
         rewriteRun(