Regex

[sahid ul karim]

I have a string like :- String str="This 'is' really good work";
i want to find 'is' . What should be the regex for this ?

[Joanne Neal]

Do you have to use regex ? str.indexOf("'is'") will do what you want.

[Bill Cruise]

The regex for 'is' is "'is'".

[Piet Verdriet]

If it's the actual String "is" you're looking for, a simple indexOf(...) will do just fine, as already suggested.
If you want to capture text between ' (single quote), here's a way to do that:

String str = "This 'is' really good work"; 
Matcher m = Pattern.compile("(?<=')[^']+(?=')").matcher(str);
System.out.println(m.find() ? m.group() : null);

[Alan Moore]

That regex is more complicated than it needs to be, Piet--or at least, more advanced. The OP didn't even mention needing to extract the word from within the apostrophes, but if you really need to, using capturing groups is simpler:

String str = "This 'is' really good work"; 
Matcher m = Pattern.compile("'([^']+)'").matcher(str);
System.out.println(m.find() ? m.group(1) : null);