Merge #184 manually (fails clean merge due to refactor b/w 2.x and 3.…

…0) (#185)

base/src/main/java/tools/jackson/jaxrs/cfg/MapperConfiguratorBase.java

@@ -2,6 +2,7 @@
 
 import java.util.EnumMap;
 import java.util.Map;
+import java.util.concurrent.locks.ReentrantLock;
 
 import tools.jackson.databind.*;
 import tools.jackson.databind.cfg.MapperBuilder;
@@ -17,6 +18,8 @@ public abstract class MapperConfiguratorBase<IMPL extends MapperConfiguratorBase
     MAPPER extends ObjectMapper
 >
 {
+    private final ReentrantLock _lock = new ReentrantLock();
+
     /*
     /**********************************************************************
     /* Configuration, simple features
@@ -87,9 +90,14 @@ public MapperConfiguratorBase(MAPPER mapper,
         _instropectorOverride = instropectorOverride;
     }
 
-    public synchronized MAPPER getDefaultMapper() {
+    public MAPPER getDefaultMapper() {
         if (_defaultMapper == null) {
-            _defaultMapper = _mapperWithConfiguration(mapperBuilder());
+            _lock.lock();
+            try {
+                _defaultMapper = _mapperWithConfiguration(mapperBuilder());
+            } finally {
+                _lock.unlock();
+            }
         }
         return _defaultMapper;
     }
@@ -102,7 +110,12 @@ public synchronized MAPPER getDefaultMapper() {
     protected MAPPER mapper()
     {
         if (_mapper == null) {
-            _mapper = _mapperWithConfiguration(mapperBuilder());
+            _lock.lock();
+            try {
+                _mapper = _mapperWithConfiguration(mapperBuilder());
+            } finally {
+                _lock.unlock();
+            }
         }
         return _mapper;
     }
@@ -127,17 +140,17 @@ protected MAPPER mapper()
     /**
      * Method that locates, configures and returns {@link ObjectMapper} to use
      */
-    public synchronized MAPPER getConfiguredMapper() {
+    public MAPPER getConfiguredMapper() {
         // important: should NOT call mapper(); needs to return null
         // if no instance has been passed or constructed
         return _mapper;
     }
 
-    public synchronized final void setMapper(MAPPER m) {
+    public final void setMapper(MAPPER m) {
         _mapper = m;
     }
 
-    public synchronized final void setAnnotationIntrospector(AnnotationIntrospector aiOverride) {
+    public final void setAnnotationIntrospector(AnnotationIntrospector aiOverride) {
         _instropectorOverride = aiOverride;
     }
 

release-notes/CREDITS-2.x

@@ -91,6 +91,8 @@ PJ Fanning (@pjfanning)
 * Contributed #166: `ProviderBase` class shows contention on synchronized
   block using `LRUMap` _writers instance
  (2.14.2)
+* Contributed #184: Use `ReentrantLock`s instead of synchronized blocks
+ (2.18.0)
 
 Steven Schlansker (@stevenschlansker)
 

release-notes/VERSION-2.x

@@ -12,7 +12,8 @@ Sub-modules:
 
 2.18.0 (not yet released)
 
-No changes since 2.17
+#184: Use `ReentrantLock`s instead of synchronized blocks
+ (contributed by @pjfanning)
 
 2.17.0 (12-Mar-2024)