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When can an object reference be cast to an interface reference
An object reference be cast to an interface reference when the object implements thereferenced interface.
Sandhya.Kishan
- Jul 25th, 2012
When an object implements the referenced interface then the object reference be cast to an interface reference.
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What is the difference between a static and a non-static inner class
A non-static inner class may have object instances that are associated with instances ofthe class's outerclass. A static inner class does not have any object instances.
Sandhya.Kishan
- Jul 25th, 2012
A static inner class need to be referred by the class name being it is static. A static inner class can have access even to the private members of the outer class. The non-static inner class has the ...
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How are commas used in the initialization and iteration parts of a for statement
Commas are used to separate multiple statements within the initialization and iterationparts of a forstatement.
Sandhya.Kishan
- Jul 24th, 2012
The multiple statements with in the initialization and in the iteration parts are separated using commas.
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What class allows you to read objects directly from a stream?
The ObjectInputStream class supports the reading of objects from input streams.
Sandhya.Kishan
- Jul 24th, 2012
The class that allows to read objects directly from a stream is the Objectinputstream class.
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What methods are used to get and set the text label displayed by a Buttonobject
getLabel() and setLabel()
Sandhya.Kishan
- Jul 24th, 2012
The methods used to get and set the text label are GetLabel() and SetLabel() methods.
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What is the difference between the Font and FontMetrics classes
The FontMetrics class is used to define implementation-specific properties, such asascent and descent, of aFont object.
Sandhya.Kishan
- Jul 24th, 2012
The Font class maps the characters of the language to their respective glyphs.
The FontMetrics provides access to attributes of Fontobjects, things such as char width, char height, which help in drawing the fonts on the screen. -
What is the purpose of the finally clause of a try-catch-finally statement
The finally clause is used to provide the capability to execute code no matter whether ornot an exception isthrown or caught.
Sandhya.Kishan
- Jul 24th, 2012
The purpose is that,when an exception is caught during program execution,code written in finally clause will be executed ,irrespective of what type of error has occurred.
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What is the purpose of finalization
The purpose of finalization is to give an unreachable object the opportunity to performany cleanupprocessing before the object is garbage collected.
Sandhya.Kishan
- Jul 24th, 2012
The purpose of finalization is to provide opportunity to an object which is unreachable to perform any cleanup process . This activity is done before the object is garbage collected.Finalization is used to invoke finalized() method
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What classes of exceptions may be thrown by a throw statement
A throw statement may throw any expression that may be assigned to the Throwabletype.
Sandhya.Kishan
- Jul 24th, 2012
Exceptions which are assigned Throwable Type are thrown by a throw statement.
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What must a class do to implement an interface
It must provide all of the methods in the interface and identify the interface in itsimplements clause.
Sandhya.Kishan
- Jul 23rd, 2012
A class should provides the definition to all the methods declared in the interface to implement an interface.
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What are the legal operands of the instanceof operator
The left operand is an object reference or null value and the right operand is a class,interface, or array type.
Sandhya.Kishan
- Jul 23rd, 2012
The legal operands of instance of operator are
1. Left operand which is an object reference.
2. Right operand which can be a class or an interface.
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What modifiers can be used with a local inner class
A local inner class may be final or abstract.
Sandhya.Kishan
- Jul 23rd, 2012
The public,private, abstract, final, protected, strictfp and static modifiers can be used with a local inner class.
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What modifiers may be used with an interface declaration
An interface may be declared as public or abstract.
Sandhya.Kishan
- Jul 23rd, 2012
The public and abstract modifiers can be used with an interface declaration.
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For which statements does it make sense to use a label
The only statements for which it makes sense to use a label are those statements that canenclose a break orcontinue statement.
Sandhya.Kishan
- Jul 21st, 2012
For statements which are enclosed by a break or a continue statement makes sense to use a label statement.
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How are the elements of a CardLayout organized
The elements of a CardLayout are stacked, one on top of the other, like a deck of cards.
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What classes of exceptions may be caught by a catch clause
A catch clause can catch any exception that may be assigned to the Throwable type. Thisincludes the Errorand Exception types.
Sandhya.Kishan
- Jul 21st, 2012
An exception which may be assigned to the Throwable type including the Error and Exception types are caught by catch clause.
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What class of exceptions are generated by the Java run-time system
The Java runtime system generates RuntimeException and Error exceptions.
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What are the drivers available?
Sandhya.Kishan
- Jul 16th, 2012
The drivers avaliable in jdbc are
Type 1: JDBC-ODBC Bridge driver (Bridge)
Type 2: Native-API/partly Java driver (Native)
Type 3: AllJava/Net-protocol driver (Middleware)
Type 4: All Java/Native-protocol driver (Pure) -
How are this and super used
This is used to refer to the current object instance. super is used to refer to the variablesand methods of the superclass of the current object instance.
Sandhya.Kishan
- Jul 14th, 2012
Super() refers to the superclass of the class where the super keyword is currently being used.It is used to call the constructor of the superclass in the base class. eg: public class Class1{ public C...
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What happens if an exception is not caught
An uncaught exception results in the uncaughtException() method of the thread'sThreadGroup being invoked, which eventually results in the termination of the programin which it is thrown.
Sandhya.Kishan
- Jul 14th, 2012
When an exception is not caught by any method then the main method throws an exception and results in the termination of that method.
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