src/java.base/share/classes/sun/invoke/util/BytecodeDescriptor.java

*** 88,100 ****
              int begc = i[0], endc = str.indexOf(';', begc);
              if (endc < 0)  return null;
              i[0] = endc+1;
              String name = str.substring(begc, endc).replace('/', '.');
              try {
!                 return (loader == null)
                      ? Class.forName(name, false, null)
                      : loader.loadClass(name);
              } catch (ClassNotFoundException ex) {
                  throw new TypeNotPresentException(name, ex);
              }
          } else if (c == '[') {
              Class<?> t = parseSig(str, i, end, loader);
--- 88,101 ----
              int begc = i[0], endc = str.indexOf(';', begc);
              if (endc < 0)  return null;
              i[0] = endc+1;
              String name = str.substring(begc, endc).replace('/', '.');
              try {
!                 Class<?> clz = (loader == null)
                                      ? Class.forName(name, false, null)
                                      : loader.loadClass(name);
+                 return c == 'Q' ? clz.asValueType() : clz.asBoxType();
              } catch (ClassNotFoundException ex) {
                  throw new TypeNotPresentException(name, ex);
              }
          } else if (c == '[') {
              Class<?> t = parseSig(str, i, end, loader);
*** 149,164 ****
          return sb.toString();
      }
  
      private static void unparseSig(Class<?> t, StringBuilder sb) {
          char c = Wrapper.forBasicType(t).basicTypeChar();
!         if (c != 'L' && c != 'Q') {
              sb.append(c);
          } else if (t == Object.class) {
              sb.append("Ljava/lang/Object;");
          } else {
              boolean lsemi = (!t.isArray());
              if (lsemi)  sb.append(c);
              sb.append(t.getName().replace('.', '/'));
              if (lsemi)  sb.append(';');
          }
      }
--- 150,167 ----
          return sb.toString();
      }
  
      private static void unparseSig(Class<?> t, StringBuilder sb) {
          char c = Wrapper.forBasicType(t).basicTypeChar();
!         if (c != 'L') {
              sb.append(c);
          } else if (t == Object.class) {
              sb.append("Ljava/lang/Object;");
          } else {
              boolean lsemi = (!t.isArray());
+             if (t == t.asValueType())
+                 c = 'Q';
              if (lsemi)  sb.append(c);
              sb.append(t.getName().replace('.', '/'));
              if (lsemi)  sb.append(';');
          }
      }