src/java.base/share/classes/java/lang/String.java

*** 128,143 ****
       */
      private static final ObjectStreamField[] serialPersistentFields =
          new ObjectStreamField[0];
  
      /**
       * Initializes a newly created {@code String} object so that it represents
       * an empty character sequence.  Note that use of this constructor is
       * unnecessary since Strings are immutable.
       */
      public String() {
!         this.value = new char[0];
      }
  
      /**
       * Initializes a newly created {@code String} object so that it represents
       * the same sequence of characters as the argument; in other words, the
--- 128,148 ----
       */
      private static final ObjectStreamField[] serialPersistentFields =
          new ObjectStreamField[0];
      
      /**
+      * a shared instance of the string value for empty strings.
+      */
+     private static final char[] EMPTY_STRING_VALUE = new char[0];
+ 
+     /**
       * Initializes a newly created {@code String} object so that it represents
       * an empty character sequence.  Note that use of this constructor is
       * unnecessary since Strings are immutable.
       */
      public String() {
!         this.value = EMPTY_STRING_VALUE;
      }
  
      /**
       * Initializes a newly created {@code String} object so that it represents
       * the same sequence of characters as the argument; in other words, the