Date Format in Java?

package com.test.application;

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Locale;

public class SampleTest {

public static void main(String[] args) {
System.out.println("dd MMM yy : "+ddMMMyyDate("2018-08-31 03:08:13"));
System.out.println("dd/mm/yy  : "+ddMMMyyyyDate("2018-08-31 03:08:13"));
System.out.println("Year of Daay : "+yearofDay("2018-08-31 03:08:13"));
}

//dd MMM yy
public static String ddMMMyyDate(String dateString) {
    Date date;
    String formattedDate = "";
    try {
        date = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss",Locale.getDefault()).parse(dateString);
        formattedDate = new SimpleDateFormat("dd MMM yy",Locale.getDefault()).format(date);
    } catch (ParseException e) {
        e.printStackTrace();
    }
    return formattedDate;
}



public static String ddMMMyyyyDate(String dateString) {
    Date date;
    String formattedDate = "";
    try {
        date = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss",Locale.getDefault()).parse(dateString);
        formattedDate = new SimpleDateFormat("dd/MM/YYYY",Locale.getDefault()).format(date);
    } catch (ParseException e) {
        e.printStackTrace();
    }
    return formattedDate;
}


//To get the year of day
public static String yearofDay(String dateString) {
    Date date;
    String formattedDate = "";
    try {
        date = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss",Locale.getDefault()).parse(dateString);
        formattedDate = new SimpleDateFormat("DD",Locale.getDefault()).format(date);
    } catch (ParseException e) {
        e.printStackTrace();
    }
    return formattedDate;
}


}

First Not Repeating Character

1. First Not Repeating Character

public class Simple{
public static void main(String args[]){

System.out.println("Result : "+firstNotRepeatingCharacter("abdecabde"));


}
public static char firstNotRepeatingCharacter(String s) {
    char[] c= s.toCharArray();
for(int i=0;i<s.length();i++){
    if(s.indexOf(c[i])==s.lastIndexOf(c[i]))
        return c[i];
}
    return '_';
}

}


2.  find century  from current year



int centuryFromYear(int year) {

     if (year % 100 == 0) {
            year = year / 100;
        } else {
            year = (year / 100) + 1;
        }
        return year;
}

File Extension Validation Example Code

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class ImageValidator{

    private Pattern pattern;
    private Matcher matcher;

    private static final String File_PATTERN =
            "([^\\s]+(\\.(?i)(jpg|png|doc|docx|pdf))$)";

    public ImageValidator(){
        pattern = Pattern.compile(IMAGE_PATTERN);
    }

    /**     * Validate image with regular expression     * @param filename image for validation     * @return true valid image, false invalid image     */    public boolean validate(final String filename){

        matcher = pattern.matcher(filename);
        return matcher.matches();

    }
}



Call Function :


boolean ImageValidator = new ImageValidator().validate(filePath.toLowerCase()) ? true : false;

Source code Url

                                              Websites URL for java Source Code




1. How to create the jar file.

http://stackoverflow.com/questions/5293321/create-a-java-executable-with-eclipse


2.

What is mean by String in java?

String :-


1. The Java String is immutable. [we can not change but a new instance create].

2. Generally String is sequence of character, but in JAVA ,String is an object.  String class is used to create string object.

Three Types of Method  inside the Comparison String :

1.  .equals() method
2.  ==  operator
3.  compareTo() method.


public class Stringcomparison {
   
    public static void main(String[] args)
    {
       
        //equal methods
       
        String s1 = "Dennis MacAlistair Ritchie";
        String s2 = "Dennis MacAlistair Ritchie";
          
        String s3 = new String("Dennis MacAlistair Ritchie");
        String s4 = "Dennis MacAlistair";
       
        System.out.println("equals : "+s1.equals(s2));
        System.out.println("equals : "+s1.equals(s3));
        System.out.println("equals : "+s1.equals(s4));
               
        // == operator
       
        System.out.println("-- operator  : "+(s1==s2));
        System.out.println(" == operator : "+(s1==s3));
        System.out.println(" == operator : "+(s1==s4));
       
        // compareTo() method
       
         System.out.println("compareTo method  : "+s1.compareTo(s2));
         System.out.println("compareTo method  : "+s1.compareTo(s3));
         System.out.println("compareTo method  : "+s1.compareTo(s4));
            }
    }