Java Interview Questions and Answers for Written Exam and Interview

Java Interview

Ques : What is the immediate superclass of Menu?

MenuItem

Ques : What is the purpose of finalization?

The purpose of finalization is to give an unreachable object the opportunity to perform any cleanup processing before the object is garbage collected.

Ques : Which class is the immediate superclass of the MenuComponent class.

Object

Ques : What invokes a thread's run() method?

After a thread is started, via its start() method or that of the Thread class, the JVM invokes the thread's run() method when the thread is initially executed.

Ques : What is the difference between the Boolean & operator and the && operator?

If an expression involving the Boolean & operator is evaluated, both operands areevaluated. Then the & operator is applied to the operand. When an expression involving the && operator is evaluated, the first operand is evaluated. If the first operand returns a value of true then the second operand is evaluated. The && operator is then applied to the first and second operands. If the first operand evaluates to false, the evaluation of the second operand is skipped.

Ques : Name three subclasses of the Component class.

Box.Filler, Button, Canvas, Checkbox, Choice, Container, Label, List, Scrollbar, or TextComponent

Ques : What is the GregorianCalendar class?

The GregorianCalendar provides support for traditional Western calendars.

Ques : Which Container method is used to cause a container to be laid out and redisplayed?

validate()

Ques : What is the purpose of the Runtime class?

The purpose of the Runtime class is to provide access to the Java runtime system.

Ques : How many times may an object's finalize() method be invoked by the garbage collector?

An object's finalize() method may only be invoked once by the garbage collector.