Language: C++

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;

public class Main {
	int DATAKIND = 26;
	public static void main(String[] args) 
	throws IOException{
		// TODO Auto-generated method stub
		new Main().run();
	}

	void run () 
		throws IOException{
		StandardIn buf = new StandardIn();
		
		char[] data = buf.getaline().toCharArray();
		int[] count = countData(data);
		
		printResult(count);
	}
	
	private void printResult(int[] count){
		for(int i=0; i<count.length; i++)
			System.out.println(gethashkey(i)+" : "+count[i]);
	}
	private int[] countData(char[] data){
		int[] count = new int[DATAKIND];
		for (int i=0; i<count.length; i++)
			count[i] = 0;
		
		for (int i=0; i<data.length; i++)
			if(Character.isAlphabetic(data[i]))
				count[hashdata(Character.toLowerCase(data[i]))] ++;
		
		return count;
	}
	
	private int hashdata(char data){
		return (int)(data-'a');
	}
	
	private String gethashkey(int data){
		return Character.toString((char)(data+'a'));
	}
}

class TempReaderCall{
	/*
	static ArrayList<String> getStdInReadlines(BufferedReader br, int line) throws IOException {
		ArrayList<String> list = new ArrayList<String>();
		for (int i = 0; i < line; i++)
			list.add(br.readLine());
		return list;
	}
	
	static ArrayList<String> getStdInReadlines(BufferedReader br, String end) throws IOException {
		ArrayList<String> list = new ArrayList<String>();
		String newdata;
		do{
			newdata =br.readLine();
			if (end.compareTo(newdata)==0)
				break;
			list.add(newdata);
		}while(newdata!=null);
		
		return list;
	}
	
	static String getStdInRead(BufferedReader br) throws IOException {
		return (br.readLine());
	}
	*/
	
	static int[] splitIntArrayFromString(String st) {
		String[] sts = st.split(" ");
		int[] data = new int[sts.length];
		
		for (int i=0;i<sts.length;i++){
			data[i] = Integer.parseInt(sts[i]);
		}
		
		return data;
	}
}

class StandardIn{
	private BufferedReader br;
	
	StandardIn(){
		br = new BufferedReader (new InputStreamReader(System.in));
	}
	
	ArrayList<String> getlines(int line) throws IOException {
		ArrayList<String> list = new ArrayList<String>();
		for (int i = 0; i < line; i++)
			list.add(br.readLine());
		return list;
	}
	
	ArrayList<String> getlines(String end) throws IOException {
		ArrayList<String> list = new ArrayList<String>();
		String newdata;
		do{
			newdata =br.readLine();
			if (end.compareTo(newdata)==0)
				break;
			list.add(newdata);
		}while(newdata!=null);
		
		return list;
	}
	
	String getaline() throws IOException {
		return (br.readLine());
	}
}

Compiler output:
a.cc:1:1: error: 'import' does not name a type
    1 | import java.io.BufferedReader;
      | ^~~~~~
a.cc:1:1: note: C++20 'import' only available with '-fmodules-ts'
a.cc:2:1: error: 'import' does not name a type
    2 | import java.io.IOException;
      | ^~~~~~
a.cc:2:1: note: C++20 'import' only available with '-fmodules-ts'
a.cc:3:1: error: 'import' does not name a type
    3 | import java.io.InputStreamReader;
      | ^~~~~~
a.cc:3:1: note: C++20 'import' only available with '-fmodules-ts'
a.cc:4:1: error: 'import' does not name a type
    4 | import java.util.ArrayList;
      | ^~~~~~
a.cc:4:1: note: C++20 'import' only available with '-fmodules-ts'
a.cc:6:1: error: expected unqualified-id before 'public'
    6 | public class Main {
      | ^~~~~~
a.cc:76:19: error: expected unqualified-id before '[' token
   76 |         static int[] splitIntArrayFromString(String st) {
      |                   ^
a.cc:86:2: error: expected ';' after class definition
   86 | }
      |  ^
      |  ;
a.cc:89:16: error: expected ':' before 'BufferedReader'
   89 |         private BufferedReader br;
      |                ^~~~~~~~~~~~~~~
      |                :
a.cc:89:17: error: 'BufferedReader' does not name a type
   89 |         private BufferedReader br;
      |                 ^~~~~~~~~~~~~~
a.cc:95:9: error: 'ArrayList' does not name a type
   95 |         ArrayList<String> getlines(int line) throws IOException {
      |         ^~~~~~~~~
a.cc:102:9: error: 'ArrayList' does not name a type
  102 |         ArrayList<String> getlines(String end) throws IOException {
      |         ^~~~~~~~~
a.cc:115:9: error: 'String' does not name a type
  115 |         String getaline() throws IOException {
      |         ^~~~~~
a.cc:118:2: error: expected ';' after class definition
  118 | }
      |  ^
      |  ;
a.cc: In constructor 'StandardIn::StandardIn()':
a.cc:92:17: error: 'br' was not declared in this scope
   92 |                 br = new BufferedReader (new InputStreamReader(System.in));
      |                 ^~
a.cc:92:26: error: expected type-specifier before 'BufferedReader'
   92 |                 br = new BufferedReader (new InputStreamReader(System.in));
      |                          ^~~~~~~~~~~~~~