src/java.base/share/classes/java/time/LocalDate.java

*** 1,7 ****
  /*
!  * Copyright (c) 2012, 2015, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.  Oracle designates this
--- 1,7 ----
  /*
!  * Copyright (c) 2012, 2016, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.  Oracle designates this
*** 1367,1376 ****
--- 1367,1393 ----
       */
      public LocalDate plusDays(long daysToAdd) {
          if (daysToAdd == 0) {
              return this;
          }
+         long dom = day + daysToAdd;
+         if (dom > 0) {
+             if (dom <= 28) {
+                 return new LocalDate(year, month, (int) dom);
+             } else if (dom <= 59) { // 59th Jan is 28th Feb, 59th Feb is 31st Mar
+                 long monthLen = lengthOfMonth();
+                 if (dom <= monthLen) {
+                     return new LocalDate(year, month, (int) dom);
+                 } else if (month < 12) {
+                     return new LocalDate(year, month + 1, (int) (dom - monthLen));
+                 } else {
+                     YEAR.checkValidValue(year + 1);
+                     return new LocalDate(year + 1, 1, (int) (dom - monthLen));
+                 }
+             }
+         }
+ 
          long mjDay = Math.addExact(toEpochDay(), daysToAdd);
          return LocalDate.ofEpochDay(mjDay);
      }
  
      //-----------------------------------------------------------------------