How to Convert Date to String in Java

Some times we need to convert java.util.Date to string in java may for displaying purpose I need it that while working on displaytag then I thought about this article to list down various way of converting this in various ways, after some reading I found that SimpleDateFormat makes this quite easy. To get the feel of Date API in java and to familiarize ourselves with these classes we will see different examples of converting date to String in our application. Both DateFormat and SimpleDateFormat class belongs java.text package and they are very powerful and you can use them for conversion. It is also good for parsing string into date and can be used to show in various locale also.

Its very easy with the use of SimpleDateFormat, here are the exact steps:

convert date to string, simpleDateFormat in Java

1) First step is to create a date format using SimpleDateFormat class

2) Call format() method of SimpleDateFormat by passing Date object this will return String representation of date into specified date format.

For complete details on available symbols for date conversion you can check java doc of DateFormat and SimpleDateFormat class. Here are some important points about SimpleDateFormat which is worth remembering

1)Common point of confusion between “m” and “M” , small case “m” represent minutes while “M” represent Month Also “d” represent date in month while “D” represent Day of week. This is most common cause of error while converting String to date and back date to string. In shot ddMMyy is not equal to DDmmyy.

2)It’s also worth noting that SimpleDateFormat are not thread-safe. They are not synchronized so its better you create separate DateFormat for each thread to avoid any race condition while parsing date in java.

It’s very important for any java developer be it senior or junior to get familiarize himself with Date, Time and Calendar API. SimpleDateFormat is an excellent utility for converting String to Date and then Date to String but you just need to be little careful with format and thread-safety .

Java Program to print Prime numbers in Java

How to print Prime numbers in Java or how to check if a number is prime or not is classical Java programming questions, mostly taught in Java programming courses. A number is called prime number if its not divisible by any number other than 1 or itself and you can use this logic to check whether a number is prime or not. This program is slightly difficult than printing even or odd number which are relatively easier Java exercises. This Simple Java program print prime number starting from 1 to 100 or any specified number. It also has a method which checks if a number is prime or not.

Here is complete sample code example to print prime numbers from 1 to any specified number. This Java program can also check if a number is prime or not as prime number checking logic is encapsulated in isPrime(int number) method.

How to reverse String in Java using Iteration and Recursion

Here is code example String reverse using iterative and recursive function written in Java. Recursive solution is just for demonstrative and education purpose, don’t use recursive solution in production code as it may result in StackOverFlowError if String to be reversed is very long String or if you have any bug in your reverse function, anyway its good test to make yourself comfortable with recursive functions in java.