Review Request: JDK-8193159: Reduce the number of classes loaded due to NativeLibrary

[mandy chung]

On 12/6/17 6:08 PM, Martin Buchholz wrote:
> Google decided that LinkedList is almost never the best choice, so any 
> use of LinkedList is discouraged.
>
> ArrayDeque's backing array never shrinks, so you might want to give it 
> an explicit initial size.
>

The initial size is 16 which is okay.  I can make it smaller instead:

-        static Deque<NativeLibrary> nativeLibraryContext = new 
LinkedList<>();
+        static Deque<NativeLibrary> nativeLibraryContext = new 
ArrayDeque<>(8);

Mandy
> On Wed, Dec 6, 2017 at 4:33 PM, mandy chung <mandy.chung at oracle.com 
> <mailto:mandy.chung at oracle.com>> wrote:
>
>     A tiny startup fix - useArrayDeque instead of LinkedList for
>     ClassLoader.NativeLibrary which is typically loaded at startup for
>     example when loading a JAR file.
>
>     Thanks
>     Mandy
>
>     diff --git
>     a/src/java.base/share/classes/java/lang/ClassLoader.java
>     b/src/java.base/share/classes/java/lang/ClassLoader.java
>     --- a/src/java.base/share/classes/java/lang/ClassLoader.java
>     +++ b/src/java.base/share/classes/java/lang/ClassLoader.java
>     @@ -38,6 +38,7 @@
>      import java.security.PrivilegedAction;
>      import java.security.ProtectionDomain;
>      import java.security.cert.Certificate;
>     +import java.util.ArrayDeque;
>      import java.util.Arrays;
>      import java.util.Collections;
>      import java.util.Deque;
>     @@ -45,7 +46,6 @@
>      import java.util.HashMap;
>      import java.util.HashSet;
>      import java.util.Hashtable;
>     -import java.util.LinkedList;
>      import java.util.Map;
>      import java.util.NoSuchElementException;
>      import java.util.Objects;
>     @@ -2496,7 +2496,7 @@
>              }
>
>              // native libraries being loaded
>     -        static Deque<NativeLibrary> nativeLibraryContext = new
>     LinkedList<>();
>     +        static Deque<NativeLibrary> nativeLibraryContext = new
>     ArrayDeque<>();
>
>              /*
>               * The run() method will be invoked when this class
>     loader becomes
>
>