Java regex always fails

Question

I have a Java regex pattern and a sentence I'd like to completely match, but for some sentencecs it erroneously fails. Why is this? (for simplicity, I won't use my complex regex, but just ".*")

System.out.println(Pattern.matches(".*", "asdf"));
System.out.println(Pattern.matches(".*", "[11:04:34] <@Aimbotter> 1 more thing"));
System.out.println(Pattern.matches(".*", "[11:04:35] <@Aimbotter> Dialogue: 0,0:00:00.00,0:00:00.00,Default,{Orginal LV,0000,0000,0000,,[???]??????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????} "));
System.out.println(Pattern.matches(".*", "[11:04:35] <@Aimbotter> Dialogue: 0,0:00:00.00,0:00:00.00,Default,{Orginal LV,0000,0000,0000,,[???]????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????} "));

Output:

true
true
true
false

Note that the fourth sentence contains 10 unicode control characters \u0085 in between the question marks, which aren't shown by normal fonts. The third and fourth sentences actually contain the same amount of characters!

Answer 1

use

Pattern.compile(".*",Pattern.DOTALL)

if you want . to match control characters. By default it only matches printable characters.

From JavaDoc:

"In dotall mode, the expression . matches any character, including a line terminator. By default this expression does not match line terminators.

Dotall mode can also be enabled via the embedded flag expression (?s). (The s is a mnemonic for "single-line" mode, which is what this is called in Perl.)"

Code in Pattern (there is your \u0085):

/**
 * Implements the Unicode category ALL and the dot metacharacter when
 * in dotall mode.
 */
static final class All extends CharProperty {
boolean isSatisfiedBy(int ch) {
    return true;
}
}

/**
 * Node class for the dot metacharacter when dotall is not enabled.
 */
static final class Dot extends CharProperty {
boolean isSatisfiedBy(int ch) {
    return (ch != '\n' && ch != '\r'
                && (ch|1) != '\u2029'
                && ch != '\u0085');
    }
}