Many Java beginners find it difficult to differentiate between == operator and the “equals()” method when comparing String variables in Java. They assume that both operations perform the same function and either one can be used to compare two string variables. I have even seen many experienced programmers committing the mistake of using “==” to […]
My earlier post on how to validate email address, SSN and phone number validation using Java regex still attracts a lot of visitors. Today I realized that another piece of data that many programmers need to validate is the date. Many Java applications have to process input date values, so I thought it will be […]
An example on how to validate if a String variable in Java has all numeric digits.
My post about Java regular expression gets a lot of hits daily. Someone commented that the regular expression I included in that post does not block certain invalid email addresses. So I updated the Java regular expression to validate email address. I am pretty sure that the following Java regular expression will validate any email […]
In Spring MVC, DispatcherServlet relies on handler mapping to determine which controller the request should be sent to. All handler mapping classes in Spring implement org.springframework.web.servlet.HandlerMapping interface. Spring distribution contains following four implementation of HandlerMapping interface. BeanNameUrlHandlerMapping SimpleUrlHandlerMapping ControllerClassNameHandlerMappign CommonsPathMapHandlerMapping BeanNameUrlHandlerMapping is the simplest of all and DispatcherServlet looks for this mapping by default. You […]
One of the welcome additions to Java language in Java 5 release is the static import declaration. static import works in the same way as traditional import declaration but it imports only the static members of a class. Traditional import declaration looks like this import java.util.*; The above statement will import all the classes under […]
In Java you can find maximum or minimum value in a numeric array by looping through the array. Here is the code to do that. public static int getMaxValue(int[] numbers){ int maxValue = numbers[0]; for(int i=1;i < numbers.length;i++){ if(numbers[i] > maxValue){ maxValue = numbers[i]; } } return maxValue; } public static int getMinValue(int[] numbers){ int […]
Reading properties file in Java is much easier than you might have thought. Following example illustrates one simple way of reading properties from a properties file. Let’s say we need to read from myConfig.properties file. The properties file has following entries. Directory = C:/prodFiles/ NumberOfFiles = 25 Extension = java Here is the java code […]
Regular Expressions offer a concise and powerful search-and-replace mechanism. They are patterns of characters used to perform a search, extract or replace operations on the given text. Regular expressions can also be used to validate that the input conforms to a given format. For example, we can use Regular Expression to check whether the user […]
Vector class in java.util package is very easy to use. You can add objects of any type in a vector. You don’t have to worry about declaring the size of the vector. You can just keep adding elements to your object and the vector will dynamically adjust the size. The vector will add elements one […]