how to check number in java

Hi all, this simple code to check number that I wrote with java code.


public boolean isNumeric(String st){ 
        try{ 
            double d = Double.parseDouble(st); 
        }catch(NumberFormatException e){ 
            return false; 
        } 
        return true; 
    }

Please enjoy and sharing your ideas!

How to check dot(.) in java code

Hi everyone, today I want to show you how to check dot(.) by using java code. The purpose of this code, we want to allow dot one time when we trigger it. example like calculator ...
Please enjoy with my code and then pls you help to comment me to improve our knowledge each other. Thanks Advance!

public boolean checkDot(String st){
    char ch[] = st.toCharArray();
    for(int i=0;i<ch.length;i++)
            if(ch[i] =='.')
                return true;
    return false;
}


This code, I allow to pass arguments as String. But you can modify it by your needs. Thanks!

How to list directories, subdirectories and files using java

Hi everyone, I welcome to my post. Today I want to show you some codes using java language to list directories, subdirectories, and  files. You can see my as below:

package com.saretsothea.files.classwork;

import java.io.File;
import java.util.Scanner;

/**
 *
 * @author Sout Saret
 */
public class ListFiles{
   public static void main(String [] args){
       Scanner sc = new Scanner(System.in);
       String folder;
       System.out.print("Please the path of folder:");
       folder =sc.nextLine();
       System.out.println("List all directories, subdirectries and files:");
       File f = new File(folder);
       System.out.println(f.getName());
       listFile(folder);
    }
  
    public static void listFile(String folder){
        try{
            File f = new File(folder);
            File[] listOfFiles = f.listFiles();
                for(int i = 0; i < listOfFiles.length; i++) {
                  if (listOfFiles[i].isFile()) {
                    System.out.println("--" + listOfFiles[i].getName());
                  } else if (listOfFiles[i].isDirectory()) {
                    System.out.println("-"+listOfFiles[i].getName());
                    listFile(listOfFiles[i].getAbsolutePath());
                  }
                }
        }catch(NullPointerException e){}
   }  

}

Thanks for reading!!!!!!!!!!!!!!