regex java: how to replace a string in a generic between the start tag and end tag of a generic -

in java, have string so:

"bla bla bla bla [back] bla bla bla [bla bla [go] bla bla bla bla [bla"  

and want find rule regex replace start tag "[" "(start)" , end tag "]" "(end)".

a "start-tag or end tag alone" should ignored.

the result following:

bla bla bla bla (start)back(end) bla bla bla [ bla bla (start)go(end) bla bla bla bla [bla 

string resultstring = subjectstring.replaceall(     "(?x)       # turn on verbose mode                    \n" +     "\\[        # match [                               \n" +     "(          # match , capture in group 1:           \n" +     "[^\\[\\]]* # number of characters except brackets\n" +     ")          # end of capturing group                  \n" +     "\\]        # match ]", "(start)$1(end)"); 

will match/replace balanced [/] pairs no brackets in-between them.