character « Pattern « Java Regex Q&A

1. java.util.regex.PatternSyntaxException: null (in java.util.regex.Pattern) error    stackoverflow.com

public void convertStrings() {
    for (int counter = 0; counter < compare.length; counter++) {
            compare[counter] = compare[counter].replace('*','_'); ...

2. Java regexp error: \( is not a valid character    stackoverflow.com

I was using java regexp today and found that you are not allowed to use the following regexp sequence

String pattern = "[a-zA-Z\\s\\.-\\)\\(]*";

3. Escape all the characters in a pattern except some metachars    stackoverflow.com

I want to allow the user use a "*" metachar in search and would like to use the pattern entered by user with Pattern.compile. So i would have to escape all ...

4. Need pattern which allows alphanumeric with 3 special character - . whitespace    stackoverflow.com

I need to validate a address field which can contain alphanumeric characters with -, . and whitespace. The first character should not be - or .. Repeated special characters (-- ...

5. java pattern with tab characters    stackoverflow.com

i have a file with lines like:

string1 (tab) sting2 (tab) string3 (tab) string4

6. Regex pattern - unprintable characters    coderanch.com

Greetings, I'm unable to figure out a pattern in regex for the following problem, I'd very much appreciate your inputs in this regard, I must validate a String, the validation rules are. The String must not start with an underscore(-), a space or an unprintable character. The string must not contain any empty spaces or unprintable characters. Except for unprintable characters ...