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String replace method issue in java

My problem is to replace only the last occurrence of a character in the string with another character. When I used the String.replace(char1, char2), it replaces all the occurrences of the character in the string.
For example, I have an address string like
String str = "Addressline1,Addressline2,City,State,Country,";.
I need to replace the occurrence of ',' at the end of the string with '.'.
My code to replace the character is
str = str.replace(str.charAt(str.lastIndexOf(",")),'.');
After replacing, the string looks like:
Addressline1.Addressline2.City.State.Country.
Is there the problem in Java SDK?. If yes, how to resolve it?

You should use String.replaceAll which use regex
str = str.replaceAll (",$", ".");
The $ mean the end of the String

The Java replace function has a method declaration of:
public String replace(char oldChar, char newChar)
According to the docs replace will:
Return a new string resulting from replacing all occurrences of oldChar in this string with newChar.
So your code:
str.charAt(str.lastIndexOf(","))
Will clearly return the character ,. replace will then replace all instances of the oldChar , with the newChar .. This explains the behavior you were seeing.
The solution that #ScaryWombat beat me to is your best option:
str = str.replaceAll(",$", ".");
Since, in regular expression terms, $ denotes the end of a String.
Hope this helps!

Regex Java when we have specific text upto a pattern

As i haven't much worked on regex, can someone help me out in getting the answer for below thing:
(1)I want to remove a text say Element
(2)It may of may not followed by delimiter say pipe(||)
I tried below thing, but it is not working in the way i want:
String str = "String:abc||Element:abc||Value:abc"; // Sample text 1
String str1 = "String:abc||Element:abc"; // Sample text 2
System.out.println(str.replaceFirst("Element.*\\||", ""));
System.out.println(str1.replaceFirst("Element.*\\||", ""));
Required output in above cases:
String:abc||Value:abc //for the first case
String:abc //for the second case

Assuming that you can decide to give another value to the original pattern which is Element in this case, you can use Pattern.quote to escape it as below:
String str = "String:abc||Element:abc||Value:abc"; // Sample text 1
String str1 = "String:abc||Element:abc"; // Sample text 2
String originalPattern = "Element";
String pattern = String.format("\\|{2}%s[^\\|]+", Pattern.quote(originalPattern));
System.out.println(str.replaceFirst(pattern, ""));
System.out.println(str1.replaceFirst(pattern, ""));
Your patter is then generic and its value is String.format("\\|{2}%s[^\\|]+", Pattern.quote(originalPattern))
Output:
String:abc||Value:abc
String:abc

You put the escape wrong. It should be:
Element(.*?\|\||.*$)
Put the escape on each pipe, and use ? for non greedy Regex so you only replace just enough string, not everything.

String text = "String:abc||Element:abc||Value:abc";
text = text.replaceAll("\\belement\\b", "");
you might need to use replace all this will replace all element from your string here i am using '\b' word boundary in java regular expression in between the words

Remove all characters before special character in android

I have to remove ## before $$ from string ##$$abxcyhshbhs##xcznbx##. I am using:
string.split("\\#");
The problem is that it also removes # after $$.

Use replace() instead.
String text = "##$$abxcyhshbhs##xcznbx##";
text = text.replace("##$$", "$$");

You can use substring method like below
string.substring(2);

If you really want to use String.split() you can do what you want by limiting the number of results by doing:
String str = "##$$abxcyhshbhs##xcznbx##";
str = str.split("##", 2)[1];
I don't know your exact issue but as has already been said, replace() or substring() is probably a better option.

If you have unknown number of # symbols before $$ and they appear not just at the beginning of the string, you can use the following replaceAll with a regex:
String re = "#+\\${2}";
String str = "##$$abxcyh###$$shbhs##xcznbx##";
System.out.println(str.replaceAll(re, "\\$\\$")); // Note escaped $ !!!
// => $$abxcyh$$shbhs##xcznbx##
// or
re = "#+(\\${2})"; // using capturing and back-references
System.out.println(str.replaceAll(re, "$1"));
See IDEONE demo.
Do not forget to assign the variable a new value when using in your code:
str = str.replaceAll("#+(\\${2})", "$1")

If your purpose is to remove ## from first occurrence of ##$$ in the string, then following code snippet will be helpful:
if(yourString.startsWith("##$$")){
yourString.replaceFirst("##$$","$$");
}
OR considering there is only single $$ in your string, following would be helpful:
String requiredString="";
String[] splitArr = yourString.split("\\$");
if ( splitArr.length > 1 ) {
requiredString = "$$" + splitArr[splitArr.length-1];
}
I have written a code snippet here. You can make changes and execute on your own.

To literally remove the first two characters, use the following:
String s = "##$$abxcyhshbhs##xcznbx##";
s.substring(2, s.length());
This doesn't do any pattern matching to look for the $$.

Java replaceAll - regex variable not replaced

I have one variable representing the regex, when run replaceAll, none of string is replaced. Please help to take a look.
String s = "Issue 3 for 5 describe the title";
String regex = "Issue\\s\\d+\\sfor\\s\\d+";
System.out.println(s.replaceAll(regex, "test"));

replaceAll returns the modified String, but it does not modify the original String, as String in Java is immutable.
You need to:
String resultString = s.replaceAll(regex, "test")
System.out.println(resultString);

Java String is immutable.
If you want to change string s use this:
s = s.replaceAll(regex, "test"));

This could be caused by the fact that in your code you have to double escape your regexp, but in the xml you don't:
String regex = "Issue\\s\\d+\\sfor\\s\\d+";
is equivalent to the parsed
<regex>Issue\s\d+\sfor\s\d+</regex>

Matching everything after the first comma in a string

I am using java to do a regular expression match. I am using rubular to verify the match and ideone to test my code.
I got a regex from this SO solution , and it matches the group as I want it to in rubular, but my implementation in java is not matching. When it prints 'value', it is printing the value of commaSeparatedString and not matcher.group(1) I want the captured group/output of println to be "v123_gpbpvl-testpv1,v223_gpbpvl-testpv1-iso"
String commaSeparatedString = "Vtest7,v123_gpbpvl-testpv1,v223_gpbpvl-testpv1-iso";
//match everything after first comma
String myRegex = ",(.*)";
Pattern pattern = Pattern.compile(myRegex);
Matcher matcher = pattern.matcher(commaSeparatedString);
String value = "";
if (matcher.matches())
value = matcher.group(1);
else
value = commaSeparatedString;
System.out.println(value);
(edit: I left out that commaSeparatedString will not always contain 2 commas. Rather, it will always contain 0 or more commas)

If you don't have to solve it with regex, you can try this:
int size = commaSeparatedString.length();
value = commaSeparatedString.substring(commaSeparatedString.indexOf(",")+1,size);
Namely, the code above returns the substring which starts from the first comma's index.
EDIT:
Sorry, I've omitted the simpler version. Thanks to one of the commentators, you can use this single line as well:
value = commaSeparatedString.substring( commaSeparatedString.indexOf(",") );

The definition of the regex is wrong. It should be:
String myRegex = "[^,]*,(.*)";

You are yet another victim of Java's misguided regex method naming.
.matches() automatically anchors the regex at the beginning and end (which is in total contradiction with the very definition of "regex matching"). The method you are looking for is .find().
However, for such a simple problem, it is better to go with #DelShekasteh's solution.

I would do this like
String commaSeparatedString = "Vtest7,v123_gpbpvl-testpv1,v223_gpbpvl-testpv1-iso";
System.out.println(commaSeparatedString.substring(commaSeparatedString.indexOf(",")+1));

Here is another approach with limited split
String[] spl = "Vtest7,v123_gpbpvl-testpv1,v223_gpbpvl-testpv1-iso".split(",", 2);
if (spl.length == 2)
System.out.println(spl[1]);
Byt IMHO Del's answer is best for your case.

I would use replaceFirst
String commaSeparatedString = "Vtest7,v123_gpbpvl-testpv1,v223_gpbpvl-testpv1-iso";
System.out.println(commaSeparatedString.replaceFirst(".*?,", ""));
prints
v123_gpbpvl-testpv1,v223_gpbpvl-testpv1-iso
or you could use the shorter but obtuse
System.out.println(commaSeparatedString.split(",", 2)[1]);