有些时候，需要对特定环境中的Java应用进行实时性能分析，大部分非开发和测试环境，一般都是用jvisualvm进行基本检测以最小化对系统的影响（其开启后，负载影响大约20%—30%），jvisualvm没有提供cli模式，只提供了GUI。在centos 6之后，默认不在安装图形化窗口如gnome，在有些生产环境中，因为网络和其他限制，无法通过系统盘或者yum安装相关界面。此时我们就需要预先在java启动脚本中进行JMX开启，在tomcat中，如下：
export CATALINA_OPTS="$JAVA_OPTS -Dcom.sun.management.jmxremote=true -Dcom.sun.management.jmxremote.port=1099 -Djava.rmi.server.hostname=172.18.30.193 -Dcom.sun.management.jmxremote.ssl=false -Dcom.sun.management.jmxremote.authenticate=false"
172.18.30.193为本机IP地址。
代理抛出异常 : java.rmi.server.ExportException: Port already in use: 1099; nested exception is:
java.net.BindException: Address already in use: JVM_Bind
上述选项必须设置在CATALINA_OPTS变量中，设置在JAVA_OPTS中，就会出现该问题。
# CATALINA_OPTS (Optional) Java runtime options used when the "start",
# "run" or "debug" command is executed.
# Include here and not in JAVA_OPTS all options, that should
# only be used by Tomcat itself, not by the stop process,
# the version command etc.
# Examples are heap size, GC logging, JMX ports etc.
# JAVA_OPTS (Optional) Java runtime options used when any command
# is executed.
# Include here and not in CATALINA_OPTS all options, that
# should be used by Tomcat and also by the stop process,
# the version command etc.
# Most options should go into CATALINA_OPTS.
由tomcat的停止脚本来看，其实是调用另外一个java运行时socket发到8005过去的，所以放置在JAVA_OPTS中导致有开启了一次JMX，所以出现这个错误。