Prior Java8
package com.stackbyt;
import java.util.HashMap;
import java.util.Map;
public class CharOccurrence {
private static void printCharOccurrence(String input){
Map<Character,Integer> charMap = new HashMap<>();
for(char ch : input.toCharArray()){
if(ch == ' ') // ignore space character
continue;
if(charMap.containsKey(ch)){
charMap.put(ch,charMap.get(ch)+1);
}else{
charMap.put(ch,1);
}
}
System.out.println(charMap);
}
public static void main(String[] args) {
printCharOccurrence("java programming ");
}
}
Using Java8
public class CharOccurrence {
public static void charOccurrenceUsingJava8(String input) {
Map<Character, Long> collectMap = input.chars()
.mapToObj(ch -> (char) ch)
.filter(ch -> ch != ' ')
.collect(Collectors.groupingBy(Function.identity(), Collectors.counting()));
System.out.println(collectMap);
}
public static void main(String[] args) {
charOccurrenceUsingJava8("java programming");
}
}