feat: add start method to JMX Connector operations

 A `start()` method was added to the JMX `Connector` operations, enabling users to start the Acceptor/Initiator after stopping it. The implementation follows coding standards and was positioned consistently with the interface. No errors were encountered with the new functionality.

Author: jetbrains-junie[bot]

quickfixj-core/src/main/java/org/quickfixj/jmx/mbean/connector/ConnectorAdmin.java

@@ -25,8 +25,10 @@
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import quickfix.Acceptor;
+import quickfix.ConfigError;
 import quickfix.Connector;
 import quickfix.Initiator;
+import quickfix.RuntimeError;
 import quickfix.Session;
 import quickfix.SessionID;
 import quickfix.SessionSettings;
@@ -142,6 +144,15 @@ private ObjectName[] toObjectNameArray(List<ObjectName> sessions) {
         return sessions.toArray(new ObjectName[sessions.size()]);
     }
 
+    public void start() throws IOException {
+        log.info("JMX operation: start {} {}", getRole(), this);
+        try {
+            connector.start();
+        } catch (ConfigError | RuntimeError e) {
+            throw JmxSupport.toIOException(e);
+        }
+    }
+
     public void stop(boolean force) {
         log.info("JMX operation: stop {} {}", getRole(), this);
         connector.stop(force);

quickfixj-core/src/main/java/org/quickfixj/jmx/mbean/connector/ConnectorAdminMBean.java

@@ -30,6 +30,13 @@ public interface ConnectorAdminMBean {
      */
     String getRole() throws IOException;
 
+    /**
+     * Start the connector.
+     *
+     * @throws IOException if there is a problem starting the connector
+     */
+    void start() throws IOException;
+
     /**
      * Stop the connector.
      *