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what is the regular expression for male and female string

I have a url like
/.../Male/...
or
/../Female/...
Now i want to do something like follows to replace the string's male female part with foo
/../foo/..
What is the regular expression for this...
currently i am doing like below but no success
url.replace("(fe)?male","foo")

You need to use replaceAll to use a regex, and the expression could be even simpler:
url.replaceAll("(Fem|M)ale","foo");
or
url.replaceAll("Female|Male","foo");

You need replaceAll(), which uses regex for find what to replace, not replace(), which finds plain text:
url = url.replaceAll("(fe)?male","foo");
Also note that String are immutable, so calling a replace method doesn't change the String, it returns a new String with the changes made, so you must assign the result back to the variable.
A better regex would be:
url = url.replaceAll("(?i)\\b(fe)?male\\b","foo");
The \b regex makes sure what's being replaced is the whole word female/male. Without \b it would replace "male" in "malediction".
The (?i) makes the match case insensitive.

You need to use replaceAll for patterns.
Also you should consider using a case-insensitive pattern, as such:
String input = ".../Female/...";
System.out.println(input.replaceAll("(?i)(fe)?male", "foo"));
Output:
.../foo/...

How can I split this?

I want to split function in java.But it s not working good.
String mystring = "ersin#$gulbahar#$ev";
String [] scripts= mystring.split("#$"); //it does not split.
how can i fix this?

String mystring = "ersin#$gulbahar#$ev";
String[] scripts = mystring.split("#\\$");
System.out.println(Arrays.toString(scripts));
OUTPUT:
[ersin, gulbahar, ev]

try this:
mystring.split("#\\$")
the split method uses a Regex to split the text, a $ character has other mean in a regex

split takes a regular expression as a parameter, and $ is a special character in a regular expression meaning "match the end of the string".
Since you want to match a literal $, not the end of the string, you need to escape it with a backslash: mystring.split("#\\$"); should work.

Escape $ in your expression: split() takes a regular expression as parameter! Common issue...

How to replace all regex string in a String object?

For a string str_in = "instance (\\w+\\s+){0,8}deleted"; how can I extract instance and deleted by using the replaceAll function?
I tried str_in = str_in.replaceAll("(\\w+\\s+){0,8}", ""); but it didn't work.

If you, as your question states, really want to use replaceAll() instead of the (in my opinion more suitable) replace(), you can use the \Q and \E markers to match the string literally:
String str_in = "instance (\\w+\\s+){0,8}deleted";
System.out.println(str_in.replaceAll("\\Q(\\w+\\s+){0,8}\\E", ""));
prints
instance deleted

You will need to escape the single characters so that they lose their regex nature:
str_in.replaceAll("\\(\\\\w\\+\\\\s\\+\\)\\{0,8\\}", "")
Each escaping backslash needs to be escaped for itself because of the string literal.

Do you mean that (\\w+\\s+){0,8} is literally in the string, and you want to remove it? You will need to escape each \ again in your replaceAll, so that they are interpreted literally, not as part of a regex, and also the ( and {.

Use str_in.replace("(\\w+\\s+){0,8}", "");
replace()
Replaces each substring of this string that matches the literal target
sequence with the specified literal replacement sequence. The
replacement proceeds from the beginning of the string to the end, for
example, replacing "aa" with "b" in the string "aaa" will result in
"ba" rather than "ab"
replaceAll()
Replaces each substring of this string that matches the given regular expression with the given replacement

Replace string by matching with the regular expressions in Java

here monitorUrl contains- http://host:8810/solr/admin/stats.jsp
and monitorUrl sometimes can be-- http://host:8810/solr/admin/monitor.jsp
So i want to replace stats.jsp and monitor.jsp to ping
if(monitorUrl.contains("stats.jsp") || monitorUrl.contains("monitor.jsp")) {
trimUrl = monitorUrl.replace("[stats|monitor].jsp", "ping");
}
Anything wrong with the above code. As I get the same value of monitorUrl in trimUrl.

Try using replaceAll instead of replace (and escape the dot as Alan pointed out):
trimUrl = monitorUrl.replaceAll("(stats|monitor)\\.jsp", "ping");
From the documentation:
replaceAll
public String replaceAll(String regex, String replacement)
Replaces each substring of this string that matches the given regular expression with the given replacement.
Note: You may also want to consider matching only after a / and checking that it is at the end of the line by using $ at the end of your regular expression.

I think this is what you're looking for:
trimUrl = monitorUrl.replaceAll("(?:stats|monitor)\\.jsp", "ping");
Explanation:
replaceAll() treats the first argument as a regex, while replace() treats it as a literal string.
You use parentheses, not square brackets, to group things. (?:...) is the non-capturing form of group; you should use the capturing form - (...) - only when you really need to capture something.
. is a metacharacter, so you need to escape it if you want to match a literal dot.
And finally, you don't have to check for the presence of the sentinel string separately; if it's not there, replaceAll() just returns the original string. For that matter, so does replace(); you could also have done this:
trimUrl = monitorUrl.replace("stats.jsp", "ping")
.replace("monitor.jsp", "ping");

No needs to use regex (also replace() don't use regex).
trimUrl = monitorUrl.replace("stats.jsp", "ping").replace("monitor.jsp", "ping");

String.replaceAll without RegEx

I'd like to replace all instances of a substring in a string but String.replaceAll() only accepts a pattern. The string that I have came from a previous match. Is it possible to add escapes to the pattern that I have or is there a version of replaceAll() in another class which accepts a literal string instead of a pattern?

Just use String.replace(CharSequence,CharSequence) rather than replaceAll.
NB: replace doesn't just replace the first occurrence, it replaces all occurrences, like replaceAll.

The method to add escapes is Pattern.quote().
String replaced = myString.replaceAll(Pattern.quote(matchingStr), replacementStr)
But as Jon says you can just use replace(). Despite the fact that it deviates from the replaceAll name, it does replace all occurrences just like replaceAll().