src/java.base/share/classes/jdk/internal/misc/VM.java

rev 52935 : 8215159: Improve initial setup of system Properties
Reviewed-by: mchung, rriggs

*** 24,33 ****
--- 24,35 ----
   */
  
  package jdk.internal.misc;
  
  import static java.lang.Thread.State.*;
+ 
+ import java.util.Collections;
  import java.util.Map;
  import java.util.Properties;
  
  public class VM {
  
*** 173,232 ****
       */
      public static Map<String, String> getSavedProperties() {
          if (savedProps == null)
              throw new IllegalStateException("Not yet initialized");
  
!         return savedProps;
      }
  
      private static Map<String, String> savedProps;
  
      // Save a private copy of the system properties and remove
      // the system properties that are not intended for public access.
      //
      // This method can only be invoked during system initialization.
!     public static void saveAndRemoveProperties(Properties props) {
          if (initLevel() != 0)
              throw new IllegalStateException("Wrong init level");
  
-         @SuppressWarnings({"rawtypes", "unchecked"})
-         Map<String, String> sp =
-             Map.ofEntries(props.entrySet().toArray(new Map.Entry[0]));
          // only main thread is running at this time, so savedProps and
          // its content will be correctly published to threads started later
!         savedProps = sp;
  
          // Set the maximum amount of direct memory.  This value is controlled
          // by the vm option -XX:MaxDirectMemorySize=<size>.
          // The maximum amount of allocatable direct buffer memory (in bytes)
          // from the system property sun.nio.MaxDirectMemorySize set by the VM.
          // If not set or set to -1, the max memory will be used
          // The system property will be removed.
!         String s = (String)props.remove("sun.nio.MaxDirectMemorySize");
          if (s == null || s.isEmpty() || s.equals("-1")) {
              // -XX:MaxDirectMemorySize not given, take default
              directMemory = Runtime.getRuntime().maxMemory();
          } else {
              long l = Long.parseLong(s);
              if (l > -1)
                  directMemory = l;
          }
  
          // Check if direct buffers should be page aligned
!         s = (String)props.remove("sun.nio.PageAlignDirectMemory");
          if ("true".equals(s))
              pageAlignDirectMemory = true;
- 
-         // Remove other private system properties
-         // used by java.lang.Integer.IntegerCache
-         props.remove("java.lang.Integer.IntegerCache.high");
- 
-         // used by sun.launcher.LauncherHelper
-         props.remove("sun.java.launcher.diag");
- 
-         // used by jdk.internal.loader.ClassLoaders
-         props.remove("jdk.boot.class.path.append");
      }
  
      // Initialize any miscellaneous operating system settings that need to be
      // set for the class libraries.
      //
--- 175,223 ----
       */
      public static Map<String, String> getSavedProperties() {
          if (savedProps == null)
              throw new IllegalStateException("Not yet initialized");
  
!         return Collections.unmodifiableMap(savedProps);
      }
  
      private static Map<String, String> savedProps;
  
      // Save a private copy of the system properties and remove
      // the system properties that are not intended for public access.
      //
      // This method can only be invoked during system initialization.
!     public static void saveProperties(Map<String, String> props) {
          if (initLevel() != 0)
              throw new IllegalStateException("Wrong init level");
  
          // only main thread is running at this time, so savedProps and
          // its content will be correctly published to threads started later
!         if (savedProps == null) {
!             savedProps = props;
!         }
  
          // Set the maximum amount of direct memory.  This value is controlled
          // by the vm option -XX:MaxDirectMemorySize=<size>.
          // The maximum amount of allocatable direct buffer memory (in bytes)
          // from the system property sun.nio.MaxDirectMemorySize set by the VM.
          // If not set or set to -1, the max memory will be used
          // The system property will be removed.
!         String s = props.get("sun.nio.MaxDirectMemorySize");
          if (s == null || s.isEmpty() || s.equals("-1")) {
              // -XX:MaxDirectMemorySize not given, take default
              directMemory = Runtime.getRuntime().maxMemory();
          } else {
              long l = Long.parseLong(s);
              if (l > -1)
                  directMemory = l;
          }
  
          // Check if direct buffers should be page aligned
!         s = props.get("sun.nio.PageAlignDirectMemory");
          if ("true".equals(s))
              pageAlignDirectMemory = true;
      }
  
      // Initialize any miscellaneous operating system settings that need to be
      // set for the class libraries.
      //