question: @ Nullable public static String extractClassName ( @ NotNull String string ) { StringBuilder sb = new StringBuilder ( string . length ( ) ) ; int n = string . length ( ) ; int i = 0 ; for ( ; i < n ; i ++ ) { char c = Character . toUpperCase ( string . charAt ( i ) ) ; if ( Character . isJavaIdentifierStart ( c ) ) { sb . append ( c ) ; i ++ ; break ; } } if ( sb . length ( ) > 0 ) { for ( ; i < n ; i ++ ) { char c = string . charAt ( i ) ; if ( Character . isJavaIdentifierPart ( c ) ) { sb . append ( c ) ; } } return sb . toString ( ) ; } return null ; }
target:  Creates a Java class name out of the given string, if possible. For example, "My Project" becomes "MyProject", "hello" becomes "Hello", "Java's" becomes "Java", and so on.