Remove Numbers in String - Java Program

public String removeNumbersInString(String str) {

        String temp = "";

        String regexp = "^[0-9]";

        Pattern pattern = Pattern.compile(regexp);

        Matcher matcher;

        if(!str.isEmpty()){

        for (int i = 0; i < str.length(); i++) {

            matcher = pattern.matcher(str.charAt(i) + "");

            if (!matcher.matches()) {

                temp = temp + str.charAt(i) + "";

            }

        }}

        System.out.println("" + temp);

        return temp;

    }

Remove String in Numbers-Java Program

public String removeStringInNumbers(String str) {

        String temp = "";

        String regexp = "^[a-zA-Z]";

        Pattern pattern = Pattern.compile(regexp);

        Matcher matcher;

        if(!str.isEmpty()){

        for (int i = 0; i < str.length(); i++) {

            matcher = pattern.matcher(str.charAt(i) + "");

            if (!matcher.matches()) {

                temp = temp + str.charAt(i) + "";

            }

        }}

        System.out.println("" + temp);

        return temp;

    }

Write an example that counts the number of times a particular character, such as e, appears in a file. The character can be specified at the command line.

import java.io.BufferedInputStream;
import java.io.FileInputStream;

class GetOccurrences{
    public static void main(String args[])
    {
        try{
            FileInputStream fis=new FileInputStream("C:\\Users\\SAN-MCA-ME-MTECH-MS\\Documents\\SAN\\Temp.txt");
            BufferedInputStream bis=new BufferedInputStream(fis);
                    
            int i;
            int occurs=0;
            
            while((i=bis.read())!=-1)
            {
                char a=(char)i;
                
                if(a==args[0].charAt(0))
                {
                 occurs++;
                }
            }
            System.out.println("Letter e  is "+occurs+" of times repeated in the file");
        }catch(Exception ex)
        {
            System.out.println(ex.getMessage());
        }
    }
}