src/java.compiler/share/classes/javax/lang/model/SourceVersion.java

*** 56,66 ****
       * 1.7: diamond syntax, try-with-resources, etc.
       * 1.8: lambda expressions and default methods
       *   9: modules, small cleanups to 1.7 and 1.8 changes
       *  10: local-variable type inference (var)
       *  11: local-variable syntax for lambda parameters
!      *  12: TBD
       *  13: TBD
       */
  
      /**
       * The original version.
--- 56,66 ----
       * 1.7: diamond syntax, try-with-resources, etc.
       * 1.8: lambda expressions and default methods
       *   9: modules, small cleanups to 1.7 and 1.8 changes
       *  10: local-variable type inference (var)
       *  11: local-variable syntax for lambda parameters
!      *  12: no changes (switch expressions in preview)
       *  13: TBD
       */
  
      /**
       * The original version.
*** 206,247 ****
          return RELEASE_13;
      }
  
      private static final SourceVersion latestSupported = getLatestSupported();
  
      private static SourceVersion getLatestSupported() {
!         try {
!             String specVersion = System.getProperty("java.specification.version");
! 
!             switch (specVersion) {
!                 case "13":
!                     return RELEASE_13;
!                 case "12":
!                     return RELEASE_12;
!                 case "11":
!                     return RELEASE_11;
!                 case "10":
!                     return RELEASE_10;
!                 case "9":
!                     return RELEASE_9;
!                 case "1.8":
!                     return RELEASE_8;
!                 case "1.7":
!                     return RELEASE_7;
!                 case "1.6":
!                     return RELEASE_6;
!             }
!         } catch (SecurityException se) {}
! 
!         return RELEASE_5;
      }
  
      /**
       * Returns the latest source version fully supported by the
!      * current execution environment.  {@code RELEASE_5} or later must
       * be returned.
       *
       * @return the latest source version that is fully supported
       */
      public static SourceVersion latestSupported() {
          return latestSupported;
      }
--- 206,245 ----
          return RELEASE_13;
      }
  
      private static final SourceVersion latestSupported = getLatestSupported();
  
+     /*
+      * The integer to release enum constant implemented by this method
+      * assumes the JEP 322: "Time-Based Release Versioning" scheme is
+      * in effect. This scheme began in JDK 10. If the JDK versioning
+      * scheme is revised, this method may need to be updated
+      * accordingly.
+      */
      private static SourceVersion getLatestSupported() {
!         int intVersion = Runtime.version().feature();
!         return (intVersion >= 11) ?
!             valueOf("RELEASE_" + Math.min(13, intVersion)):
!             RELEASE_10;
      }
  
      /**
       * Returns the latest source version fully supported by the
!      * current execution environment.  {@code RELEASE_9} or later must
       * be returned.
       *
+      * @apiNote This method is included alongside {@link latest} to
+      * allow situations where the language model API is running on a
+      * platform version different than the latest version modeled by
+      * the API to be identified. One way that sort of situation can
+      * occur is if a IDE or similar tool is using the API to model
+      * source version <i>N</i> while running on platform version
+      * (<i>N</i>&nbsp;-&nbsp;1). Running in this configuration is
+      * supported by the API. Running an API on platform versions
+      * earlier than (<i>N</i>&nbsp;-&nbsp;1) or later than <i>N</i>
+      * may or may not work as an implementation detail.
+      *
       * @return the latest source version that is fully supported
       */
      public static SourceVersion latestSupported() {
          return latestSupported;
      }