[pytorch] Revert InstanceHolder for PyTorch engine (#2876)

Fixes: #2875
deepjavalibrary · Nov 26, 2023 · e45f344 · e45f344
1 parent 50f8af6
commit e45f344
Showing 1 changed file with 10 additions and 5 deletions.
diff --git a/engines/pytorch/pytorch-engine/src/main/java/ai/djl/pytorch/engine/PtEngineProvider.java b/engines/pytorch/pytorch-engine/src/main/java/ai/djl/pytorch/engine/PtEngineProvider.java
@@ -18,6 +18,8 @@
 /** {@code PtEngineProvider} is the PyTorch implementation of {@link EngineProvider}. */
 public class PtEngineProvider implements EngineProvider {
 
+    private static volatile Engine engine; // NOPMD
+
     /** {@inheritDoc} */
     @Override
     public String getEngineName() {
@@ -33,10 +35,13 @@ public int getEngineRank() {
     /** {@inheritDoc} */
     @Override
     public Engine getEngine() {
-        return InstanceHolder.INSTANCE;
-    }
-
-    private static class InstanceHolder {
-        static final Engine INSTANCE = PtEngine.newInstance();
+        if (engine == null) {
+            synchronized (PtEngineProvider.class) {
+                if (engine == null) {
+                    engine = PtEngine.newInstance();
+                }
+            }
+        }
+        return engine;
     }
 }