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Is there a way of checking for multiple string sequences with String.matches in Java?

I want to look for any of the following sequences: either one of * - / + followed by a * + /
for example:
4+*2 is something I am looking for.
4+5/2 is not
if (combinedArray.matches("[-*+/][*+/]"))
{
...code
}
I'd be happy to know what I did wrong.
I basicly want it to have the same logic as this:
if (combinedArray.contains("*/") | combinedArray.contains("*+") | combinedArray.contains("**")
| combinedArray.contains("//") | combinedArray.contains("/+") | combinedArray.contains("/*")
| combinedArray.contains("+/") | combinedArray.contains("++") | combinedArray.contains("+*")
| combinedArray.contains("-/") | combinedArray.contains("-+") | combinedArray.contains("-*") )
~~~

Match text between empty lines

I have a text in following blocks:
AAAAAAA
BBBBBBB
CCCCCCC
DDDDDD. YYYYYYYYYYYYYYYYYYYYYY
EEEEE 1234567890
Some random text
Some text random
Random text
Text
Some random text
ZZZZZZZZZZZZZZZZ
UUUUUUUUUUUUUUUU
How to select with regexp a following block?
Some random text
Some text random
Random text
Text
Some random text
From the original text I know that this block goes after line DDDDDD. YYYYYYYYYYYYYYYYYYYYYY which is optionally followed by line EEEEE 1234567890 and also that block is between lines that contain only \s symbols.
I have tried pattern DDDDDD.*\\s+(.*)\\s+ it doesn't work.

You can use the following Pattern to match your expected text:
String text = "AAAAAAA\nBBBBBBB\nCCCCCCC\n\nDDDDDD. YYYYYYYYYYYYYYYYYYYYYY "
+ "\nEEEEE 1234567890 "
+ "\n\nSome random text\nSome text random\nRandom text\nText \nSome random text\n\n"
+ "ZZZZZZZZZZZZZZZZ\nUUUUUUUUUUUUUUUU";
Pattern p = Pattern.compile(
// | 6 "D"s
// | | actual dot
// | | | some whitespace
// | | | | 22 "Y"s
// | | | | | more whitespace
// | | | | | | optional:
// | | | | | || 5 "E"s
// | | | | | || | whitespace
// | | | | | || | | 10 digits
// | | | | | || | | | more whitespace including line breaks
// | | | | | || | | | | your text
// | | | | | || | | | | | followed by any "Z" sequence
"D{6}\\.\\s+Y{22}\\s+(E{5}\\s\\d{10}\\s+)?(.+?)(?=Z+)",
Pattern.DOTALL
);
Matcher m = p.matcher(text);
if (m.find()) {
System.out.println(m.group(2));
}
Output
Some random text
Some text random
Random text
Text
Some random text
Note
Not sure how to delimit the final part, so I just used a capitalized Z sequence (1+).
Up to you to refine.

Setting up a Regex Pattern in Java

I am having some difficulty trying to create a working regex pattern for recognizing a string of file names.
Pattern pattern = Pattern.compile("(\\w+)(\\.)(t)(x)(t)(\\s$|\\,)");
When using a .find() from a matcher class on my sample input, say
"file1.txt,file2.txt "
I am returned true, which is fine, however other erroneous input also returns true.
This erroneous input includes strings such as:
"file1.txt,,file2.txt "
"file%.text "
I have been consulting this website as I have been trying to construct them, I'm pretty sure I am missing something rather obvious though. Link

To validate your file name list, you can use the following solution:
// | preceded by start of input, or
// | | comma, preceded itself by either word or space
// | | | file name
// | | | | dot
// | | | | | extension
// | | | | | | optional 1 space
// | | | | | | | followed by end of input
// | | | | | | | | or comma,
// | | | | | | | | followed itself by word character
Pattern pattern = Pattern.compile("(?<=^|(?<=[\\w\\s]),)(\\w+)(\\.)txt\\s?(?=$|,(?=\\w))");
String input = "file1.txt,file2.txt";
String badInput = "file3.txt,,file4.txt";
String otherBadInput = "file%.txt, file!.txt";
Matcher m = pattern.matcher(input);
while (m.find()) {
// printing group 1: file name
System.out.println(m.group(1));
}
m = pattern.matcher(badInput);
// won't find anything
while (m.find()) {
// printing group 1: file name
System.out.println(m.group(1));
}
m = pattern.matcher(otherBadInput);
// won't find anything
while (m.find()) {
// printing group 1: file name
System.out.println(m.group(1));
}
Output
file1
file2

May this help you:
Pattern pattern = Pattern.compile("(.*?\\.\\w+)(?:,|$)");
String files = "file1.txt,file2.txt";
Matcher mFile = pattern.matcher(files);
while (mFile.find()) {
System.out.println("file: " + mFile.group(1));
}
Output:
file: file1.txt
file: file2.txt
With only .txt files: (.*?\\.txt)(?:,|$)

Naive way :
public boolean validateFileName(String string){
String[] fileNames= string.split(",");
Pattern pattern = Pattern.compile("\b[\w]*[.](txt)\b"); /*match complete name, not just pattern*/
for(int i=0;i<fileNames.length;i++){
Matcher m = p.matcher(fileNames[i]);
if (!m.matches())
return false;
}
return true;
}

Pattern p = Pattern.compile("((\\w+\\.txt)(,??|$))+");
The above Pattern lets "file1.txt,,file2.txt" pass, but does not get an empty file for the two commas.
The other Strings "file1.txt,file2.txt" and "file%txt" are processed correctly.

Regular Expression in Java for UMASK

I need a Java regular expression to get the following two values:
the value of the UMASK parameter in file /etc/default/security should be set to 077. [Current value: 022] [AA.1.9.3]
the value of UMASK should be set to 077 in /etc/skel/.profile [AA.1.9.3]
I need to get the file name from the input string, as well as the current value if existing.
I wrote a regex as .* (.*?/.*?) (?:\\[Current value\\: (\\d+)\\])?.* for this one, it can match both strings, also to get the file name, but can NOT get the current value.
Then another regex: .* (.*?/.*?) (?:\\[Current value\\: (\\d+)\\])? .* comparing with the first one, there is a space before the last .* for this one, it can match the string 1, and get file name and current value, but it can NOT match the string 2...
What how can I correct these regular expressions to obtain the values described above?

If I understand your requisites correctly (file name and current octal permissions value), you can use the following Pattern:
String input =
"Value for parameter UMASK in file /etc/default/security should be set to 077. " +
"[Current value: 022] [AA.1.9.3] - " +
"Value of UMASK should be set to 077 in /etc/skel/.profile [AA.1.9.3]";
// | "file " marker
// | | group 1: the file path
// | | | space after
// | | || any characters
// | | || | escaped square bracket
// | | || | | "Current value: " marker
// | | || | | | group 2:
// | | || | | | digits for value
// | | || | | | | closing bracket
Pattern p = Pattern.compile("file (.+?) .+?\\[Current value: (\\d+)\\]");
Matcher m = p.matcher(input);
// iterates, but will find only once in this instance (which is desirable)
while (m.find()) {
System.out.printf("File: %s%nCurrent value: %s%n", m.group(1), m.group(2));
}
Output
File: /etc/default/security
Current value: 022

Matching "\n" in string

This may have been asked before but I haven't come across an answer. I have a string that looks like
" ___________________ \n|_ | ___ _ _|\n| | | _|___|"
which I am passing to a java program as a command line argument. Literally just paste that string as a command line argument.
The first line in my program is
String [] array = args[0].split("\n");
I want to split it on the "\n" but I can't seem to do it with split("\n") or split("\\n"). What am I doing wrong?

try
String str =" ___________________ \n|_ | ___ _ _|\n| | | _|___|";
String[] arr = str.split("\n");
System.out.println(Arrays.deepToString(arr));

Try this
String lines[] = String.split("\\r?\\n");

String data=" ___________________ \n|_ | ___ _ _|\n| | | _|___|";
String data1[]=data.split("\\n");
System.out.println(data);
Gives output.
___________________
|_ | ___ _ _|
| | | _|___|

\n - New Line Feed
\r - Carriage Return
String input = "___________________ \n|_ | ___ _ _|\n| | | _|___|";
String[] splitValue = input.split("[\\r\\n]+");

If your string is passed in containing literal backslashes you have to match it using split("\\\\n").
Explanation: to match a backslash in regex you have to excape it, so the regex is \\n. To input this through a java String-literal you have to excape each of the two backslashes in the regex, so it becomes "\\\\n".
...just don't ask me about matching double backslashes ;-)