--- old/src/jdk.jdi/share/classes/com/sun/tools/jdi/EventSetImpl.java	2020-04-15 11:02:29.000000000 -0700
+++ new/src/jdk.jdi/share/classes/com/sun/tools/jdi/EventSetImpl.java	2020-04-15 11:02:29.000000000 -0700
@@ -425,16 +425,17 @@
         }
 
         public String className() {
+            // trim leading "L" and trailing ";"
             String name = classSignature.substring(1, classSignature.length() - 1);
-            int index = name.indexOf(".");  // check if it's a hidden class
+            int index = name.indexOf(".");  // check if it is a hidden class
             if (index < 0) {
-                name = name.replace('/', '.');
-            } else {
-                // the class name of a hidden class is <binary-name> + "/" + <suffix>
-                name = name.substring(0, index).replace('/', '.') + "/" +
-                         name.substring(index + 1, name.length());
+                return name.replace('/', '.');
+            }  else {
+                // map the type descriptor from: "L" + N + "." + <suffix> + ";"
+                // to class name: N.replace('/', '.') + "/" + <suffix>
+                return name.substring(0, index).replace('/', '.')
+                        + "/" + name.substring(index + 1);
             }
-            return name;
         }
 
         public String classSignature() {