Class Overview
Thrown when a program tries to access a field or method of an object or an
element of an array when there is no instance or array to use, that is if the
object or array points to null
. It also occurs in some other, less
obvious circumstances, like a throw e
statement where the Throwable
reference is null
.
Summary
Public Constructors |
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NullPointerException()
Constructs a new NullPointerException that includes the current
stack trace.
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NullPointerException(String detailMessage)
Constructs a new NullPointerException with the current stack
trace and the specified detail message.
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[Expand]
Inherited Methods |
From class
java.lang.Throwable
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From class
java.lang.Object
Object
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clone()
Creates and returns a copy of this Object .
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boolean
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equals(Object o)
Compares this instance with the specified object and indicates if they
are equal.
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void
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finalize()
Invoked when the garbage collector has detected that this instance is no longer reachable.
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final
Class<?>
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getClass()
Returns the unique instance of Class that represents this
object's class.
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int
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hashCode()
Returns an integer hash code for this object.
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final
void
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notify()
Causes a thread which is waiting on this object's monitor (by means of
calling one of the wait() methods) to be woken up.
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final
void
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notifyAll()
Causes all threads which are waiting on this object's monitor (by means
of calling one of the wait() methods) to be woken up.
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String
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toString()
Returns a string containing a concise, human-readable description of this
object.
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final
void
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wait()
Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object.
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final
void
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wait(long millis, int nanos)
Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the
specified timeout expires.
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final
void
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wait(long millis)
Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the
specified timeout expires.
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Public Constructors
public
NullPointerException
()
Constructs a new NullPointerException
that includes the current
stack trace.
public
NullPointerException
(String detailMessage)
Constructs a new NullPointerException
with the current stack
trace and the specified detail message.
Parameters
detailMessage
| the detail message for this exception.
|