Java Enum was one of the best features added on JDK 1.5 Tiger release along with Generics, Autoboxing, and varargs. Enum in Java represents fixed number of well-known things e.g. number of days in Week, the number of months in the calendar year etc. Unlike C and C++ Enum in Java are much powerful and they are not an integer constant, Instead, Enum is a Type like class or interface which provides compile time type safety. In this Java Enum tutorial, we will see a couple of important points about Java Enum which help to understand Enum better and get most out of it. I have written in the style of FAQ i.e. frequently asked questions, this will help you to learn more about Java Enum's capability and features e.g. whether Enum can extend class or implement methods or not? When you can override methods inside enum? whether you can compare Enum using equals() or == in Java? etc
Reading input and password in Java using java.io.Console - Example tutorial
Java 6 added a new utility class for reading input data from character based devices including command line. java.io.Console can be used to read input from command line, but unfortunately, it doesn't work on most of the IDE like Eclipse and Netbeans. As per Javadoc call to System.Console() will return attached console to JVM if it has been started interactive command prompt or it will return null if JVM has been started using a background process or scheduler job. Anyway, java.io.Console not only provides a way to read input from command prompt or Console but also reading passwords from the console without echoing it. Console.readPassword() method reads password and returns a character array and password is masked during entering so that any peeping tom can not see your password while you are entering it.
How to Iterate over Java Enum : values() Example
Enum Values() Example
In this Java programming tutorial, we will learn how to iterate over enum in Java. Since Enums are a collection of a finite number of well-known objects, often we need to iterate over them. Enums are also final in Java and has a private constructor, which means you can not create enum instances once declared. Iteration over Enum is extremely simple, provided you know about implicit values() method, which is a static method, provided by java.lang.Enum. Since every enum in Java extends java.lang.Enum, they all get this implicit values() method. Actually there are couple of them, e.g. valueOf(), name(), ordinal() etc. This method returns enum constants in the order they are declared in Enum class. Even the ordinal() method returns the same order.
In this Java programming tutorial, we will learn how to iterate over enum in Java. Since Enums are a collection of a finite number of well-known objects, often we need to iterate over them. Enums are also final in Java and has a private constructor, which means you can not create enum instances once declared. Iteration over Enum is extremely simple, provided you know about implicit values() method, which is a static method, provided by java.lang.Enum. Since every enum in Java extends java.lang.Enum, they all get this implicit values() method. Actually there are couple of them, e.g. valueOf(), name(), ordinal() etc. This method returns enum constants in the order they are declared in Enum class. Even the ordinal() method returns the same order.
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