Avoid useless stacktraces in log.

joram/a3/rt/src/main/java/fr/dyade/aaa/agent/AgentServer.java

@@ -1257,15 +1257,17 @@ public final class AgentServer {
             String tname = dis.readUTF();
             transaction = (Transaction) Class.forName(tname).newInstance();
           } catch (Exception exc) {
+            if (logmon.isLoggable(BasicLevel.DEBUG))
               logmon.log(BasicLevel.FATAL,
                        getName() + ", can't instantiate transaction manager", exc);
-            throw new Exception("Can't instantiate transaction manager");
+            throw new Exception("Can't instantiate transaction manager: " + exc.getMessage());
           } finally {
             if (dis != null) dis.close();
           }
           try {
             transaction.init(path);
           } catch (IOException exc) {
+            if (logmon.isLoggable(BasicLevel.DEBUG))
               logmon.log(BasicLevel.FATAL,
                        getName() + ", can't start transaction manager", exc);
             throw new Exception("Can't start transaction manager: " + exc.getMessage());
@@ -1544,7 +1546,10 @@ public final class AgentServer {
         logmon.log(BasicLevel.ERROR, getName() + " jmx failed", exc);
       }
     } catch (Exception exc) {
-      logmon.log(BasicLevel.ERROR, getName() + "Cannot initialize", exc);
+      if (logmon.isLoggable(BasicLevel.DEBUG))
+          logmon.log(BasicLevel.ERROR, getName() + " cannot initialize", exc);
+      else
+        logmon.log(BasicLevel.ERROR, getName() + " cannot initialize: " + exc.getMessage());
       synchronized(status) {
         // AF: Will be replaced by a BAD_INITIALIZED status allowing the
         // re-initialization..
@@ -1552,7 +1557,10 @@ public final class AgentServer {
       }
       throw exc;
     } catch (Throwable t) {
+      if (logmon.isLoggable(BasicLevel.DEBUG))
       logmon.log(BasicLevel.ERROR, getName() + "Cannot initialize", t);
+      else
+        logmon.log(BasicLevel.ERROR, getName() + " cannot initialize: " + t.getMessage());
       synchronized(status) {
         // AF: Will be replaced by a BAD_INITIALIZED status allowing the
         // re-initialization..