If you want to delete all characters in Other/Control Unicode category, you can do something like this:
System.out.println(
"a\u0000b\u0007c\u008fd".replaceAll("\\p{Cc}", "")
); // abcd
Note that this actually removes (among others) '\u008f' Unicode character from the string, not the escaped form "%8F" string.
If the blacklist is not nicely captured by one Unicode block/category, Java does have a powerful character class arithmetics featuring intersection, subtraction, etc that you can use. Alternatively you can also use a negated whitelist approach, i.e. instead of explicitly specifying what characters are illegal, you specify what are legal, and everything else then becomes illegal.
API links
Examples
Here's a subtraction example:
System.out.println(
"regular expressions: now you have two problems!!"
.replaceAll("[a-z&&[^aeiou]]", "_")
);
// _e_u_a_ e___e__io__: _o_ _ou _a_e __o __o__e__!!
The […] is a character class. Something like [aeiou] matches one of any of the lowercase vowels. [^…] is a negated character class. [^aeiou] matches one of anything but the lowercase vowels.
[a-z&&[^aeiou]] matches [a-z] subtracted by [aeiou], i.e. all lowercase consonants.
The next example shows the negated whitelist approach:
System.out.println(
"regular expressions: now you have two problems!!"
.replaceAll("[^a-z]", "_")
);
// regular_expressions__now_you_have_two_problems__
Only lowercase letters a-z are legal; everything else is illegal.