Class java.lang.Object
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Class java.lang.Object
java.lang.Object
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public class
Object
The root of the Class hierarchy. Every Class in the system
has Object as its ultimate parent. Every variable and method
defined here is available in every Object.
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See Also:
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Class
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Version:
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1.25, 08/18/95
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Object()
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clone()
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Creates a clone of this Object.
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copy(Object)
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Copies the contents of the specified Object into this Object.
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equals(Object)
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Compares two Objects for equality.
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getClass()
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Returns the Class of this Object.
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hashCode()
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Returns a hashcode for this Object.
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notify()
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Notifies a single waiting thread on a change in condition of another thread.
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notifyAll()
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Notifies all of the threads waiting for a condition to change.
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toString()
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Returns a String that represents the value of this Object.
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wait(long)
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Causes a thread to wait until it is notified or the specified timeout
expires.
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wait(long, int)
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More accurate wait.
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wait()
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Causes a thread to wait forever until it is notified.
Object
public Object()
getClass
public final Class getClass()
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Returns the Class of this Object. Java has a runtime
representation for classes- a descriptor of type Class-
which the method getClass() returns for any Object.
hashCode
public int hashCode()
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Returns a hashcode for this Object.
Each Object in the Java system has a hashcode. The hashcode
is a number that is usually different for different Objects.
It is used when storing Objects in hashtables.
Note: hashcodes can be negative as well as positive.
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See Also:
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Hashtable
equals
public boolean equals(Object obj)
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Compares two Objects for equality.
Returns a boolean that indicates whether this Object is equivalent
to the specified Object. This method is used when an Object is stored
in a hashtable.
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Parameters:
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obj
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the Object to compare with
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Returns:
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true if these Objects are equal; false otherwise.
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See Also:
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Hashtable
copy
protected void copy(Object src)
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Copies the contents of the specified Object into this Object. The contents
of an Object are defined as the values of its instance variables. The
parameter src must be of the same Class as this Object.
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Parameters:
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src
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the Object whose contents are copied into the current object
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Throws: ClassCastException
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If obj is not of the same type as
this Object.
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See Also:
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clone
clone
protected Object clone()
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Creates a clone of this Object. A new instance is allocated and
the copy() method is called to copy the contents of this
Object into the clone.
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Returns:
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a copy of this Object.
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Throws: OutOfMemoryError
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If there is not enough memory.
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See Also:
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copy
toString
public String toString()
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Returns a String that represents the value of this Object. It is recommended
that all subclasses override this method.
notify
public final void notify()
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Notifies a single waiting thread on a change in condition of another thread.
The thread effecting the change notifies the waiting thread
using notify(). Threads that want to wait for a condition to
change before proceeding can call wait().
The method notify() can only be called from within a synchronized method.
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Throws: InternalError
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If the current thread is not the owner of the
Object's monitor.
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See Also:
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wait,
notifyAll
notifyAll
public final void notifyAll()
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Notifies all of the threads waiting for a condition to change.
Threads that are waiting are generally waiting for another thread to
change some condition. Thus, the thread effecting a change that more
than one thread is waiting for notifies all the waiting threads using
the method notifyAll(). Threads that want to wait for a condition to
change before proceeding can call wait().
The method notifyAll() can only be called from within a synchronized method.
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Throws: InternalError
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If the current thread is not the owner of the
Object's monitor.
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See Also:
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wait,
notify
wait
public final void wait(long timeout) throws InterruptedException
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Causes a thread to wait until it is notified or the specified timeout
expires.
The method wait() can only be called from within a synchronized method.
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Parameters:
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timeout
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the maximum time to wait in milliseconds
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Throws: InternalError
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If the current thread is not the owner of the
Object's monitor.
wait
public final void wait(long timeout,
int nanos) throws InterruptedException
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More accurate wait.
The method wait() can only be called from within a synchronized method.
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Parameters:
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timeout
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the maximum time to wait in milliseconds
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nano
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additional time, in nanoseconds range 0-999999
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Throws: InternalError
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If the current thread is not the owner of the
Object's monitor.
wait
public final void wait() throws InterruptedException
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Causes a thread to wait forever until it is notified.
The method wait() can only be called from within a synchronized method
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Throws: InternalError
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If the current thread is not the owner of the
Object's monitor.
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