(jena) branch main updated: GH-2787: Use lazy holder pattern for system initialization

[andy]

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andy pushed a commit to branch main
in repository https://gitbox.apache.org/repos/asf/jena.git


The following commit(s) were added to refs/heads/main by this push:
     new 0f9ff7dbe0 GH-2787: Use lazy holder pattern for system initialization
0f9ff7dbe0 is described below

commit 0f9ff7dbe0bea67966a79c2b89734b77703db5ea
Author: Andy Seaborne <a...@apache.org>
AuthorDate: Tue Oct 29 11:10:09 2024 +0000

    GH-2787: Use lazy holder pattern for system initialization
---
 .../src/main/java/org/apache/jena/sys/JenaSystem.java   | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/jena-core/src/main/java/org/apache/jena/sys/JenaSystem.java 
b/jena-core/src/main/java/org/apache/jena/sys/JenaSystem.java
index 09871f83b9..5602bcbf56 100644
--- a/jena-core/src/main/java/org/apache/jena/sys/JenaSystem.java
+++ b/jena-core/src/main/java/org/apache/jena/sys/JenaSystem.java
@@ -77,20 +77,23 @@ public class JenaSystem {
     }
 
     public static void init() {
-        // Once jena is initialized, all calls are an immediate return.
         if ( initialized )
             return ;
-        // Overlapping attempts to perform initialization will block on the 
synchronized.
-        synchronized(JenaSystem.class) {
-            if ( initialized )
-                return ;
+        // Access the initialized flag to trigger class loading
+        var unused = LazyInitializer.IS_INITIALIZED;
+    }
+
+    private static class LazyInitializer {
+        static final boolean IS_INITIALIZED = jenaSystemInitialization();
+
+        private static boolean jenaSystemInitialization() {
+            JenaSystem.initialized = true; // Set early to avoid blocking on 
static initialization.
             setup();
             if ( DEBUG_INIT )
                 singleton.debug(DEBUG_INIT);
             singleton.initialize();
             singleton.debug(false);
-            // Last so overlapping initialization waits on the synchronized
-            initialized = true;
+            return true;
         }
     }