first,use jdb command to start the log program

then set some breakpoints as follows:

stop at ch.qos.logback.core.spi.AppenderAttachableImpl:50

stop at ch.qos.logback.core.spi.AppenderAttachableImpl:51

stop at ch.qos.logback.core.joran.spi.ConfigurationWatchList:83

stop at ch.qos.logback.core.spi.AppenderAttachableImpl:109

 

run

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hit breakpoint ch.qos.logback.core.spi.AppenderAttachableImpl:50

find main thread id,  suspend 【main thread id】, execute cont command

 

 

hit breakpoint  ch.qos.logback.core.joran.spi.ConfigurationWatchList:83

now ,let us change our config file ,save it, 

go back to debug tool interface,execute cont command

 

hit breakpoint ch.qos.logback.core.spi.AppenderAttachableImpl:109

execute next command, appenderList will be cleared, suspend current thread id,

and  resume main thread,   then let us execute cont command

 

hit breakpoint  ch.qos.logback.core.spi.AppenderAttachableImpl:51

step debug from here, u can find something as follows: