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Which class is extended by all other classes
The Object class is extended by all other classes.
Sandhya.Kishan
- Jun 2nd, 2012
The object class is the super class of each and every class and henae it is extended by all other classes.
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How are the elements of a BorderLayout organized
The elements of a BorderLayout are organized at the borders (North, South, East, andWest) and the centerof a container.
Sandhya.Kishan
- Jun 2nd, 2012
The elements of a borderlayout are organized in the center and at the borders of the container.
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What method is invoked to cause an object to begin executing as a separatethread
The start() method of the Thread class is invoked to cause an object to begin executing asa separate thread.
Sandhya.Kishan
- Jun 2nd, 2012
To cause an object to begin executing as a separate thread we should invoke the start() method present in the thread class.
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What is the purpose of the Runtime class
The purpose of the Runtime class is to provide access to the Java runtime system.
Sandhya.Kishan
- Jun 2nd, 2012
The runtime class provides access to the java runtime system, it provides runtime information memory availability, invoking the garbage collector.It provides facilities such as Reading data through key board,Running non-java programs from within a java application etc.
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What restrictions are placed on the location of a package statement within asource code file
A package statement must appear as the first line in a source code file (excluding blanklines andcomments).
Sandhya.Kishan
- Jun 2nd, 2012
The restriction on the location of the package statement is that it should appear as the first line with in a source code file.
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Why are the methods of the Math class static
So they can be invoked as if they are a mathematical code library.
Sandhya.Kishan
- Jun 1st, 2012
Math class contains methods used for mathematical calculations since they do not depend on instance data to perform their job and hence they are static.
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How are this() and super() used with constructors
This() is used to invoke a constructor of the same class. super() is used to invoke asuperclass constructor.
Sandhya.Kishan
- Jun 1st, 2012
If we want to execute the constructor before executing the functionality of a method then we use this() constructor.This()refers the current constructor. When we want to invoke the constructor of the...
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What is the difference between a field variable and a local variable
A field variable is a variable that is declared as a member of a class. A local variable is avariable that isdeclared local to a method.
Sandhya.Kishan
- Jun 1st, 2012
1.A field variable is a variable which is declared as a member of a class where as a local variable is declared in a method which belongs to a class. 2.Field variables are alive as long as the instanc...
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Which class is the immediate superclass of the Container class
Component
Sandhya.Kishan
- May 30th, 2012
The immediate super class of the container class is java.awt.Compnoent
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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.
Sandhya.Kishan
- May 30th, 2012
Error exceptions and run time exceptions are generated by the Java run-time system.
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How can the Checkbox class be used to create a radio button
By associating Checkbox objects with a CheckboxGroup.
Sandhya.Kishan
- May 30th, 2012
Checkbox objects can be associated with a CheckboxGroup such that the checkbox class can be used to create a radio button.
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Which non-Unicode letter characters may be used as the first character of anidentifier
The non-Unicode letter characters $ and _ may appear as the first character of anidentifier
Sandhya.Kishan
- May 30th, 2012
Ampersand "$" is the non-unicode letter characters which can be used as the first character of an identifier.
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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
- May 30th, 2012
The class allows to read objects directly from a stream is the ObjectInputStream class.
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Name four Container classes
Window, Frame, Dialog, FileDialog, Panel, Applet, or ScrollPane
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What is the return type of a program's main() method
A program's main() method has a void return type.
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What restrictions are placed on method overloading
Two methods may not have the same name and argument list but different return types.
Sandhya.Kishan
- May 30th, 2012
In method overloading
1.methods should have the same name.
2.The methods may or may not have return type and the return type may or may not be the same.
The signature should be different. -
Implicit objects of jsp are available in destroy() method or not?
Sandhya.Kishan
- May 30th, 2012
No the implicit objects of JSP are not available in destroy() method. The destroy method is invoked by the container when a JSP page is about to be destroyed.It can be overridden by a page author to p...
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What happens when you add a double value to a String
The result is a String object.
Sandhya.Kishan
- May 26th, 2012
When we add a double value to a string then the resulting value is a string object.
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What is a void return type
A void return type indicates that a method does not return a value.
Sandhya.Kishan
- May 26th, 2012
If a function does not return any value then it is of void return type.
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What is the difference between a Scrollbar and a ScrollPane
A Scrollbar is a Component, but not a Container. A ScrollPane is a Container. AScrollPane handles itsown events and performs its own scrolling.
Sandhya.Kishan
- May 24th, 2012
*A scroll-bar is a component. *A scroll bar provides a convenient means for allowing a user to select from a range of values. *Scroll-bars can either be vertical or horizontal. *It has multiples compo...
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