81. If a variable
is declared as private, where may the variable be accessed?
A private
variable may only be accessed within the class in which it is declared.
82. What is an
object's lock and which object's have locks?
An object's lock
is a mechanism that is used by multiple threads to obtain synchronized access
to the object. A thread may execute a synchronized method of an object only
after it has acquired the object's lock. All objects and classes have locks. A
class's lock is acquired on the class's Class object.
83. What is the
Dictionary class?
The Dictionary
class provides the capability to store key-value pairs.
84. How are the
elements of a BorderLayout organized?
The elements of a
BorderLayout are organized at the borders (North, South, East, and West) and
the center of a container.
85. What is the %
operator?
It is referred to
as the modulo or remainder operator. It returns the remainder of dividing the
first operand by the second operand.
86. When can an
object reference be cast to an interface reference?
An object
reference be cast to an interface reference when the object implements the
referenced interface.
87. What is the
difference between a Window and a Frame?
The Frame class
extends Window to define a main application window that can have a menu bar.
88. Which class
is extended by all other classes?
The Object class
is extended by all other classes.
89. Can an object
be garbage collected while it is still reachable?
A reachable
object cannot be garbage collected. Only unreachable objects may be garbage
collected..
90. Is the
ternary operator written x : y ? z or x ? y : z ?
It is written x ?
y : z.
91. What is the
difference between the Font and FontMetrics classes?
The FontMetrics
class is used to define implementation-specific properties, such as ascent and
descent, of a Font object.
92. How is
rounding performed under integer division?
The fractional
part of the result is truncated. This is known as rounding toward zero.
93. What happens
when a thread cannot acquire a lock on an object?
If a thread
attempts to execute a synchronized method or synchronized statement and is
unable to acquire an object's lock, it enters the waiting state until the lock
becomes available.
94. What is the
difference between the Reader/Writer class hierarchy and the
InputStream/OutputStream
class hierarchy?
The Reader/Writer
class hierarchy is character-oriented, and the InputStream/OutputStream class
hierarchy is byte-oriented.
95. 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. This
includes the Error and Exception types.
96. If a class is
declared without any access modifiers, where may the class be accessed?
A class that is
declared without any access modifiers is said to have package access. This
means that the class can only be accessed by other classes and interfaces that
are defined within the same package.
97. What is the
SimpleTimeZone class?
The
SimpleTimeZone class provides support for a Gregorian calendar.
98. What is the
Map interface?
The Map interface
replaces the JDK 1.1 Dictionary class and is used associate keys with values.
99. Does a class
inherit the constructors of its superclass?
A class does not
inherit constructors from any of its superclasses.
100. 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 can enclose a break or continue
statement.
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