Java regex match stack overflow

Question

Pattern eqPattern = Pattern.compile("(.*?)([a-z0-9\\_\\.]*) eq \"(((\\\\\")|[^\"])*)\"([\\s]*.*)", Pattern.CASE_INSENSITIVE);

This is my regex. When I try to match a long string, I got stack overflow. The pattern will match something like column1 eq "abc" and column ne "abc"; (\\\")|[^\"]): to skip " in inside "". I want to ask how to rewrite this to prevent stack overflow.

Answer 1

The best approach is to remove the alternation from the regex.
That can be done like this, which uses the unrolled loop instead:

"(.*?)([\\w.]*) eq \"([^\"\\\\]*(?:\\\\[\\S\\s][^\"\\\\]*)*)\"(\\s*.*)"

Raw and Expanded

 ( .*? )                       # (1)
 ( [\w.]* )                    # (2)
 [ ] eq [ ] 
 "
 (                             # (3 start)
      [^"\\]* 
      (?:

           \\ [\S\s] 
           [^"\\]* 
      )*
 )                             # (3 end)
 "
 ( \s* .* )                    # (4)