read unique char: 'あ' from json file in java

I am reading a JSON file in Java using this code:

String data = Files.readFile(jsonFile)
    .trim()
    .replaceAll("[^\\x00-\\x7F]", "")
    .replaceAll("[\\p{Cntrl}&&[^\r\n\t]]", "")
    .replaceAll("\\p{C}", "");

In my JSON file, there is a unique char: 'あ' (12354) that is interpreted to: "" (nothing) when reading the file.

How can I make this char show up in my variable "data"?

Due to answers I've got, I understand that the data is cleaned from high ASCII characters by adding replaceAll("[^\\x00-\\x7F]", ""). But what can I do if I want all high ASCII characters to be cleaned except this one 'あ'?

The character you want is the unicode character HIRAGANA LETTER A and has code U+3042.

You can simply add it to the list of valid characters:

...
.replaceAll("[^\\x00-\\x7F\\u3042]", "")
...