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Name four Container classes
Window, Frame, Dialog, FileDialog, Panel, Applet, or ScrollPane
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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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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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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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Under what conditions is an object's finalize() method invoked by the garbagecollector
The garbage collector invokes an object's finalize() method when it detects that the objecthas becomeunreachable.
Sandhya.Kishan
- Jun 11th, 2012
When an object has no references then it reaches its unreachable condition and under this condition the finalize() method is invoked by the garbage collector.
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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 relationship between a method's throws clause and the exceptionsthat can bethrown during the method's execution
A method's throws clause must declare any checked exceptions that are not caught withinthe body of themethod.
Sandhya.Kishan
- Jul 31st, 2012
Any checked exceptions that are not caught within the body of the method must declare in a methods throws clause.
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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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What Checkbox method allows you to tell if a Checkbox is checked
getState()
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What state is a thread in when it is executing
An executing thread is in the running state.
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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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How are the elements of a GridLayout organized
The elements of a GridBad layout are of equal size and are laid out using the squares of agrid.
Sandhya.Kishan
- Jun 4th, 2012
The elements of a gridlayout are organized depending on the size and equal size are laid out using the squares of a grid.
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What an I/O filter
An I/O filter is an object that reads from one stream and writes to another, usuallyaltering the data in someway as it is passed from one stream to another.
Sandhya.Kishan
- Jul 31st, 2012
To read from one stream and then to write on other stream we use i/o filter.
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If an object is garbage collected, can it become reachable again
Once an object is garbage collected, it ceases to exist. It can no longer become reachableagain.
Sandhya.Kishan
- May 22nd, 2012
An object reaches the garbage collection once it becomes unreachable and it cannot become reachable again.
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What is the Set interface
The Set interface provides methods for accessing the elements of a finite mathematicalset. Sets do notallow duplicate elements.
Sandhya.Kishan
- Jun 12th, 2012
The Set interface extends the Collection interface.It contains only methods inherited from Collection interface,some methods are: 1.add( )-Adds an object to the collection. 2.clear( )-Removes all obj...
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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.
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What are E and PI
E is the base of the natural logarithm and PI is mathematical value pi.
Sandhya.Kishan
- Jun 2nd, 2012
E and Pi are mathematical constants where E stands foe natural logarithm and PI stands for a value equal to 3.17
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Are true and false keywords
The values true and false are not keywords.
Sandhya.Kishan
- May 22nd, 2012
No true and false are not keywords but they can only be the return types of a boolean data type.
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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 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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