Java Queries

What is the preferred size of a component?

The preferred size of a component is the minimum component size that will allow the component to display normally.

Is null a keyword?

The null value is not a keyword.

What's new with the stop(), suspend() and resume() methods in JDK 1.2?

The stop(), suspend() and resume() methods have been deprecated in JDK 1.2.

Can a lock be acquired on a class?

Yes, a lock can be acquired on a class. This lock is acquired on the class's Class object..

What is synchronization and why is it important?

With respect to multi threading, synchronization is the capability to control the access of multiple threads to shared resources. Without synchronization, it is possible for one thread to modify a shared object while another thread is in the process of using or updating that object's value.

How are Observer and Observable used?

Objects that subclass the Observable class maintain a list of observers. When an Observable object is updated it invokes the update() method of each of its observers to notify the observers that it has changed state. The Observer interface is implemented by objects that observe Observable objects.

Why do threads block on I/O?

Threads block on i/o (that is enters the waiting state) so that other threads may execute while the i/o Operation is performed.

which containers use a border Layout as their default layout?

The window, Frame and Dialog classes use a border layout as their default layout.

Explain the life cycle methods of a JSP?

• JSPs Pre-translated: Before the JSP file has been translated and compiled into the Servlet.
• JSPs Translated: The JSP file has been translated and compiled as a Servlet.
• Initialized: Prior to handling the requests in the service method the container calls the jspInit() to initialize the Servlet.

What is a JSP? What is it used for? What do you understand by the term JSP translation phase or compilation

JSP (Java ServerPages) is an extension of the Java Servlet technology. JSP is commonly used as the presentation layer for combining HTML and Java code. While Java Servlet technology is capable of generating HTML with out.println(“….. �) statements, where out is a PrintWriter.