Validation

In this post, we will see how to do input validation in java using Scanner class. The Java Scanner class is used to get input from user. It provides several methods to get input of different types and to validate the input as well. Here we will see some of these methods that can be […]

In this post, we will see how to validate a password in java. Here are rules for password: Must have at least one numeric character Must have at least one lowercase character Must have at least one uppercase character Must have at least one special symbol among @#$% Password length should be between 8 and […]

In this post, we will see about regex to find currency symbols in a text. You can use below regex to find currency symbols in any text. \\p{Sc} Each unicharacter belongs to certain category and you can search for it using /p. Sc is short code for current symbol, so using \p{Sc}, we are trying […]

In this post, we will see about Luhn Algorithm in java Introduction Luhn algorithm, also known as modulus 10 or mod 10 algorithm, is a simple checksum process for validating various identification numbers such as credit card numbers, Canadian social securities numbers. This algorithm is designed to protect again mistyped or accidental error rather than […]

In this post, we will about Objects class’s isNull method. Objects’s isNull() method is used to check if object is null or not. java.util.Objects class was introduced in java 7. Here is simple example for Object's isNull method. [crayon-6629b673d7345730171659/] Output: Is str1 null: false Is str2 null: true Let’s look at source code Object’s isNull() […]

In this post, we will see how to validate phone number in java. Validate any international phone number as per E.123 E.123 is a standards-based recommendation by the International Telecommunications Union sector ITU-T. E.123 provides following specifications. The leading plus (+) serves as an international prefix symbol, and is immediately followed by the country code […]

In this post, we will see how to validate email address in java. There are times when you have to validate email address provided by user. You might want to write your own logic to validate email addresses but there are lots of standard regular expressions or libraries which can help you validate email address […]

In this post, we will see how to create regex alphanumeric which will create only alphanumeric characters. There are times when you need to validate the user’s input. It should contain only characters from a-z, A-Zor 0-9. Here is simple regex for it. ^[a-zA-Z0-9]*$ Here is the explaination of above regex. ^ : start of […]