Highlight search phrase in search result using Oracle Database 12c and Java

There is an easy way, and a hard way for solving this. First I'll talk about the hard way. I have an existing web service which has a search feature. The search feature works fine in Oracle 12c as long as I escape all of the necessary special/reserved characters that a user may enter in. The problem is in highlighting the search results in Java. The two different searches don't match up. For example, Oracle database 12c will find 100 records, but the highlight function, doesn't always find the same number of words or phrases because it uses a different REGEX search system. The highlight function's purpose is to take the results from the database search, and find the start and stop index, so that each word or phrase can be highlighted on the front end. In summary, the user should be able to type _any_ random characters in the search field and the highlight function should find the same number of occurrences as the Oracle Database search. If the search function finds 63 records, which contain a total of 78 occurrences of the search word or phrase, then the highlight function should find all 78 of them also, no matter what the user searches for. example inputs and outputs: Input: #%@//(*$HF\#E<)@R}#>R""2^r4' _#$RFDdfs"{ Record: fwed#%@//(*$HF\#E<)@R}#>R""2^r4' _#$RFDdfs"{f4 f 33 fwef <> fewf#%@//(*$HF\#E<)@R}#>R""2^r4' _#$RFDdfs"{ 86 45%$ 4%^&^&fdd !* Result: (4, 44), (71, 115) (The result is saying it found two occurrences. One from index 4 to 44, and another at index 71 to 115.) Again, this needs to work no matter what the user enters in the search box. This is easy to do for normal letters, not not so easy for any random character. There may be an easier way of doing this if you can get Oracle Database to tell you the indexes of exactly where it found the search string within the CLOB field, (at each occurrence). I have not been able to find a function for that though. After all special characters in searchString have been escaped, the database search is performed like this: String query = "select * from sys.my_table WHERE CONTAINS(my_clob_field, '" + searchString + "', 1) > 0"; The results are a list of strings, which are then searched to find the start and stop indexes so that the words can be highlighted. You do not need any code from me. You can just create a command line program in Java that generates some number of records with random characters in a CLOB field. Then your program would just run the search to test the accuracy of the results. If you solved it the easy way, then there isn't much testing to do. If you had to do it the hard way, then you will need to test that the highlight function correctly finds the search phrase that the initial database search found.