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h2/src/main/org/h2/jdbcx/JdbcDataSourceFactory.java

@@ -76,11 +76,13 @@ implements ObjectFactory
 //## Java 1.4 end ##
 
     private TraceSystem getTraceSystem() {
-        if (cachedTraceSystem == null) {
-            cachedTraceSystem = new TraceSystem(SysProperties.CLIENT_TRACE_DIRECTORY + "h2datasource" + Constants.SUFFIX_TRACE_FILE, false);
-            cachedTraceSystem.setLevelFile(SysProperties.DATASOURCE_TRACE_LEVEL);
+        synchronized (JdbcDataSourceFactory.class) {
+            if (cachedTraceSystem == null) {
+                cachedTraceSystem = new TraceSystem(SysProperties.CLIENT_TRACE_DIRECTORY + "h2datasource" + Constants.SUFFIX_TRACE_FILE, false);
+                cachedTraceSystem.setLevelFile(SysProperties.DATASOURCE_TRACE_LEVEL);
+            }
+            return cachedTraceSystem;
         }
-        return cachedTraceSystem;
     }
 
     Trace getTrace() {

h2/src/main/org/h2/jdbcx/JdbcXAConnection.java

@@ -506,6 +506,9 @@ implements XAConnection, XAResource
         }
 
         protected void finalize() {
+            // don't call super.finalize because
+            // this should print its own stack trace,
+            // and would close the connection
             if (!SysProperties.runFinalize) {
                 return;
             }