java.util.UnknownFormatConversionException: Conversion = '#'

Question

This my code and it throws an exception while formatting the string with use of String.Format Java native method.

String value = "#%1$s#.*?%#";
String patt = String.format(value);    

java.util.UnknownFormatConversionException: Conversion = '#'

at java.util.Formatter.checkText(Unknown Source)

at java.util.Formatter.parse(Unknown Source)

at java.util.Formatter.format(Unknown Source)

at java.util.Formatter.format(Unknown Source)

at java.lang.String.format(Unknown Source)

Any idea what's wrong?

Answer 1

you have to add string format to format the string you want. Ex :

String value = "#%1$s#.*?%#";
String patt = String.format("%s",value);

System.out.println(patt);

Read this

Answer 2

There are two format methods:

public static String format(String format, Object... args)  

and

public static String format(Locale locale, String format, Object... args)  

locale : specifies the locale to be applied on the format() method.

format : format of the string.

args : arguments for the format string. It may be zero or more

So in your case, whatever format you are specifying is not proper I guess.

You can check different format which you can use over here: https://dzone.com/articles/java-string-format-examples

Answer 3

The value:

String value = "#%1$s#.*?%#";

can't contain the character % . It is used as a reserverd word.