I have a string like "isnull(col_name,0)<>1 or isnull(col1_name,0)=0 and isnull(col2_name,0)>=100... " I want to convert above string in below form as: " (col_name is null or col_name<>1) or (col1_name is null or col1_name=0) and (col2_name is null or col2_name>=100) ... " I want to implement this in JAVA. I have tried with using split function but the case is not the similar everytime(means is between two there may be 'OR' or 'AND', so how to split?). Then I tried with contains function but how to replace that complete part of isnull in required form. (I have also tried with using character array,it works somewhat fine but fails somewhere according to my code.) Actually I tried a lot with different ways but I am not able to build the good logic which will work fast. Pls suggest me some good idea for this. Sorry for my bad english. Thanks.