To Count the number of occurrences of a char in a String.

To Count the number of duplicate of a char in a String.

String str = "";

 Scanner in= new Scanner(System.in);
 System.out.println("Please enter a String");

 str=in.nextLine();

 System.out.println("Please enter a Character");
 String chr=in.next();

 int charCount = str.length() - str.replaceAll("a", "").length();

 System.out.println("Number of occurances of given character:"+charCount);