Skills required for Sun test CX310-055

Sun has specified more than thirty five objectives for Sun test CX310-055 (Sun Certified Programmer for the Java 2 Platform, Standard Edition 5.0), which are grouped under Seven topics. Before taking the test, an individual should posses a good command over the following areas: Developing......[read more]

What is a Scanner?

Scanner is a class present in the java.util package. Like the BufferedReader class, this class is used to take user inputs. However, unlike BufferedReader, which throws checked IOException, it does not throw any checked exception. In addition to taking an input from the user, it is also used to......[read more]

What is the wait() method?

The wait() method is final and belongs to the Object class. It provides a way for a shared object to pause a thread when it becomes unavailable to that thread. This method is called in the synchronized context and can only be called on a thread when it holds a lock. ...[read more]

What is the Map interface?

Map is a generic interface of the Collections API defined as follows: interface Map <key, value> The Map interface defines a family of collection classes that map keys to values. There are generally no restrictions on the class of a key or the class of a value. Each key corresponds......[read more]

What is a constructor?

A constructor is a special type of method. It initializes an object immediately upon creation. It has the same name as the class in which it resides. A constructor is automatically called immediately after an object is created, before the new operator completes. A constructor can be marked as......[read more]

What is serialization?

Serialization is the process of converting the state of an object into a form that can be transported or stored. In this process, an object's state is written to a temporary or persistent storage. Later, the object can be recreated by deserializing or reading the object's state from the storage....[read more]

What is the ClassCastException?

The ClassCastException is thrown to show an invalid cast. It indicates that the code has attempted to cast an object to a subclass of which it is not an instance. It is also thrown when an attempt is made to add an incompatible object to a collection. The syntax of the ClassCastException is......[read more]

What is a JAR file?

A JAR (Java Archive) file is a utility for bundling and deploying Java programs. It is a kind of zip file, created using the JAR tool. Usually, a JAR file contains class files, image files, and audio/video files. It also contains a manifest file, which contains information such as whether the......[read more]

What is the List interface?

The List interface extends the Collection interface and allows duplicate elements to be added to itself. The elements of a List are stored in a sequence. They can be inserted or accessed by their position in the list, using a zero-based index. The List interface is generic. Its syntax is as......[read more]

What is the DateFormat class?

DateFormat is an abstract class that is used to format the date and time. This class extends the java.util.Format class. The important methods of the DateFormat class are as follows: static final DateFormat getInstance() : This method returns the default date/time formatter that uses the SHORT......[read more]