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java.lang.Object
Object is the root of the class hierarchy.
Every class has Object as a superclass. All objects,
including arrays, implement the methods of this class.
Object()
clone()
equals(Object)
finalize()
getClass()
hashCode()
notify()
notifyAll()
toString()
wait()
wait(long)
wait(long, int)
Object
public Object()
getClass
public final native Class getClass()
Class that represents the
runtime class of the object.
hashCode
public native int hashCode()
java.util.Hashtable.
The general contract of hashCode is:
hashCode method
must consistently return the same integer. This integer need not
remain consistent from one execution of an application to another
execution of the same application.
equals
method, then calling the hashCode method on each of the
two objects must produce the same integer result.
equals
public boolean equals(Object obj)
The equals method implements an equivalence relation:
x,
x.equals(x) should return true.
x and
y, x.equals(y) should return
true if and only if y.equals(x) returns
true.
x,
y, and z, if x.equals(y)
returns true and y.equals(z) returns
true, then x.equals(z) should return
true.
x
and y, multiple invocations of x.equals(y)
consistently return true or consistently return
false.
x, x.equals(null)
should return false.
The equals method for class Object implements the most
discriminating possible equivalence relation on objects; that is,
for any reference values x and y, this
method returns true if and only if x and
y refer to the same object (x==y has the
value true).
true if this object is the same as the obj
argument; false otherwise.
clone
protected native Object clone() throws CloneNotSupportedException
The clone method of class Object will
only clone an object whose class indicates that it is willing for
its instances to be cloned. A class indicates that its instances
can be cloned by declaring that it implements the
Cloneable interface.
Cloneable interface. Subclasses
that override the clone method can also
throw this exception to indicate that an instance cannot
be cloned.
toString
public String toString()
toString method returns a string that
"textually represents" this object. The result should
be a concise but informative representation that is easy for a
person to read.
It is recommendedthat all subclasses override this method.
The toString method for class Object
returns a string consisting of the name of the class of which the
object is an instance, the at-sign character `@', and
the unsigned hexadecimal representation of the hash code of the
object.
notify
public final native void notify()
wait methods.
This method should only be called by a thread that is the owner of this object's monitor. A thread becomes the owner of the object's monitor in one of three ways:
synchronized statement
that synchronizes on the object.
Class, by executing a
synchronized static method of that class.
Only one thread at a time can own an object's monitor.
notifyAll
public final native void notifyAll()
wait methods.
This method should only be called by a thread that is the owner
of this object's monitor. See the notify method for a
description of the ways in which a thread can become the owner of
a monitor.
wait
public final native void wait(long timeout) throws InterruptedException
The current thread must own this object's monitor. The thread releases ownership of this monitor and waits until either of the following two conditions has occurred:
notify method
or the notifyAll method.
timeout
argument in milliseconds, has elapsed.
The thread then waits until it can re-obtain ownership of the monitor and resumes execution.
This method should only be called by a thread that is the owner
of this object's monitor. See the notify method for a
description of the ways in which a thread can become the owner of
a monitor.
wait
public final void wait(long timeout,
int nanos) throws InterruptedException
This method is similar to the wait method of one
argument, but it allows finer control over the amount of time to
wait for a notification before giving up.
The current thread must own this object's monitor. The thread releases ownership of this monitor and waits until either of the following two conditions has occurred:
notify method
or the notifyAll method.
timeout
milliseconds plus nanos nanoseconds arguments, has
elapsed.
The thread then waits until it can re-obtain ownership of the monitor and resumes execution
This method should only be called by a thread that is the owner
of this object's monitor. See the notify method for a
description of the ways in which a thread can become the owner of
a monitor.
wait
public final void wait() throws InterruptedException
The current thread must own this object's monitor. The thread
releases ownership of this monitor and waits until another thread
notifies threads waiting on this object's monitor to wake up
either through a call to the notify method or the
notifyAll method. The thread then waits until it can
re-obtain ownership of the monitor and resumes execution.
This method should only be called by a thread that is the owner
of this object's monitor. See the notify method for a
description of the ways in which a thread can become the owner of
a monitor.
finalize
protected void finalize() throws Throwable
finalize method to dispose of
system resources or to perform other cleanup.
Any exception thrown by the finalize method causes
the finalization of this object to be halted, but is otherwise
ignored.
The finalize method in Object does
nothing.
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