8257872: UL: -Xlog does not check number of options

Reviewed-by: dholmes, iklam, ysuenaga

Author: jyukutyo

src/hotspot/share/logging/logConfiguration.cpp

@@ -362,10 +362,15 @@ bool LogConfiguration::parse_command_line_arguments(const char* opts) {
       *next = '\0';
       str = next + 1;
     } else {
+      str = NULL;
       break;
     }
   }
 
+  if (str != NULL) {
+    log_warning(logging)("Ignoring excess -Xlog options: \"%s\"", str);
+  }
+
   // Parse and apply the separated configuration options
   char* what = substrings[0];
   char* output = substrings[1];