/*
 
* Copyright (c) 1994, 2012, Oracle and/or its affiliates. All rights reserved.
 
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 
*
 
* This code is free software; you can redistribute it and/or modify it
 
* under the terms of the GNU General Public License version 2 only, as
 
* published by the Free Software Foundation.
  
Oracle designates this
 
* particular file as subject to the "Classpath" exception as provided
 
* by Oracle in the LICENSE file that accompanied this code.
 
*
 
* This code is distributed in the hope that it will be useful, but WITHOUT
 
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 
* FITNESS FOR A PARTICULAR PURPOSE.
  
See the GNU General Public License
 
* version 2 for more details (a copy is included in the LICENSE file that
 
* accompanied this code).
 
*
 
* You should have received a copy of the GNU General Public License version
 
* 2 along with this work; if not, write to the Free Software Foundation,
 
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 
*
 
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 
* or visit www.oracle.com if you need additional information or have any
 
* questions.
 
*/

package java.lang;

/**
 
* Class {@code Object} is the root of the class hierarchy.
 
* Every class has {@code Object} as a superclass. All objects,
 
* including arrays, implement the methods of this class.
 
*
 
* @author
  
unascribed
 
* @see
     
java.lang.Class
 
* @since
   
JDK1.0
 
*/

public class Object {

    
private static native void registerNatives();
    
static {
        
registerNatives();
    
}

    
/**
     
* Returns the runtime class of this {@code Object}. The returned
     
* {@code Class} object is the object that is locked by {@code
     
* static synchronized} methods of the represented class.
     
*
     
* <p><b>The actual result type is {@code Class<? extends |X|>}
     
* where {@code |X|} is the erasure of the static type of the
     
* expression on which {@code getClass} is called.</b> For
     
* example, no cast is required in this code fragment:</p>
     
*
     
* <p>
     
* {@code Number n = 0;
                             
}<br>
     
* {@code Class<? extends Number> c = n.getClass(); }
     
* </p>
     
*
     
* @return The {@code Class} object that represents the runtime
     
*
         
class of this object.
     
* @jls 15.8.2 Class Literals
     
*/

    
public final native Class<?> getClass();

    
/**
     
* Returns a hash code value for the object. This method is
     
* supported for the benefit of hash tables such as those provided by
     
*
 
.
     
* <p>
     
* The general contract of {@code hashCode} is:
     
* <ul>
     
* <li>Whenever it is invoked on the same object more than once during
     
*an execution of a Java application, the {@code hashCode} method
     
*must consistently return the same integer, provided no information
     
*used in {@code equals} comparisons on the object is modified.
     
*This integer need not remain consistent from one execution of an
     
*application to another execution of the same application.
     
* <li>If two objects are equal according to the {@code equals(Object)}
     
*method, then calling the {@code hashCode} method on each of
     
*the two objects must produce the same integer result.
     
* <li>It is <em>not</em> required that if two objects are unequal
     
*according to the {@link java.lang.Object#equals(java.lang.Object)}
     
*method, then calling the {@code hashCode} method on each of the
     
*two objects must produce distinct integer results.
  
However, the
     
*programmer should be aware that producing distinct integer results
     
*for unequal objects may improve the performance of hash tables.
     
* </ul>
     
* <p>
     
* As much as is reasonably practical, the hashCode method defined by
     
* class {@code Object} does return distinct integers for distinct
     
* objects. (This is typically implemented by converting the internal
     
* address of the object into an integer, but this implementation
     
* technique is not required by the
     
* Java&trade; programming language.)
     
*
     
* @return
  
a hash code value for this object.
     
* @seejava.lang.Object#equals(java.lang.Object)
     
* @seejava.lang.System#identityHashCode
     
*/

    
public native int hashCode();

    
/**
     
* Indicates whether some other object is "equal to" this one.
     
* <p>
     
* The {@code equals} method implements an equivalence relation
     
* on non-null object references:
     
* <ul>
     
* <li>It is <i>reflexive</i>: for any non-null reference value
     
*{@code x}, {@code x.equals(x)} should return
     
*{@code true}.
     
* <li>It is <i>symmetric</i>: for any non-null reference values
     
*{@code x} and {@code y}, {@code x.equals(y)}
     
*should return {@code true} if and only if
     
*{@code y.equals(x)} returns {@code true}.
     
* <li>It is <i>transitive</i>: for any non-null reference values
     
*{@code x}, {@code y}, and {@code z}, if
     
*{@code x.equals(y)} returns {@code true} and
     
*{@code y.equals(z)} returns {@code true}, then
     
*{@code x.equals(z)} should return {@code true}.
     
* <li>It is <i>consistent</i>: for any non-null reference values
     
*{@code x} and {@code y}, multiple invocations of
     
*{@code x.equals(y)} consistently return {@code true}
     
*or consistently return {@code false}, provided no
     
*information used in {@code equals} comparisons on the
     
*objects is modified.
     
* <li>For any non-null reference value {@code x},
     
*{@code x.equals(null)} should return {@code false}.
     
* </ul>
     
* <p>
     
* The {@code equals} method for class {@code Object} implements
     
* the most discriminating possible equivalence relation on objects;
     
* that is, for any non-null reference values {@code x} and
     
* {@code y}, this method returns {@code true} if and only
     
* if {@code x} and {@code y} refer to the same object
     
* ({@code x == y} has the value {@code true}).
     
* <p>
     
* Note that it is generally necessary to override the {@code hashCode}
     
* method whenever this method is overridden, so as to maintain the
     
* general contract for the {@code hashCode} method, which states
     
* that equal objects must have equal hash codes.
     
*
     
* @param
   
objthe reference object with which to compare.
     
* @return
  
{@code true} if this object is the same as the obj
     
*
          
argument; {@code false} otherwise.
     
* @see#hashCode()
     
* @seejava.util.HashMap
     
*/

    
public boolean equals(Object obj) {
        
return (this == obj);
    
}

    
/**
     
* Creates and returns a copy of this object.
  
The precise meaning
     
* of "copy" may depend on the class of the object. The general
     
* intent is that, for any object {@code x}, the expression:
     
* <blockquote>
     
* <pre>
     
* x.clone() != x</pre></blockquote>
     
* will be true, and that the expression:
     
* <blockquote>
     
* <pre>
     
* x.clone().getClass() == x.getClass()</pre></blockquote>
     
* will be {@code true}, but these are not absolute requirements.
     
* While it is typically the case that:
     
* <blockquote>
     
* <pre>
     
* x.clone().equals(x)</pre></blockquote>
     
* will be {@code true}, this is not an absolute requirement.
     
* <p>
     
* By convention, the returned object should be obtained by calling
     
* {@code super.clone}.
  
If a class and all of its superclasses (except
     
* {@code Object}) obey this convention, it will be the case that
     
* {@code x.clone().getClass() == x.getClass()}.
     
* <p>
     
* By convention, the object returned by this method should be independent
     
* of this object (which is being cloned).
  
To achieve this independence,
     
* it may be necessary to modify one or more fields of the object returned
     
* by {@code super.clone} before returning it.
  
Typically, this means
     
* copying any mutable objects that comprise the internal "deep structure"
     
* of the object being cloned and replacing the references to these
     
* objects with references to the copies.
  
If a class contains only
     
* primitive fields or references to immutable objects, then it is usually
     
* the case that no fields in the object returned by {@code super.clone}
     
* need to be modified.
     
* <p>
     
* The method {@code clone} for class {@code Object} performs a
     
* specific cloning operation. First, if the class of this object does
     
* not implement the interface {@code Cloneable}, then a
     
* {@code CloneNotSupportedException} is thrown. Note that all arrays
     
* are considered to implement the interface {@code Cloneable} and that
     
* the return type of the {@code clone} method of an array type {@code T[]}
     
* is {@code T[]} where T is any reference or primitive type.
     
* Otherwise, this method creates a new instance of the class of this
     
* object and initializes all its fields with exactly the contents of
     
* the corresponding fields of this object, as if by assignment; the
     
* contents of the fields are not themselves cloned. Thus, this method
     
* performs a "shallow copy" of this object, not a "deep copy" operation.
     
* <p>
     
* The class {@code Object} does not itself implement the interface
     
* {@code Cloneable}, so calling the {@code clone} method on an object
     
* whose class is {@code Object} will result in throwing an
     
* exception at run time.
     
*
     
* @returna clone of this instance.
     
* @throws
  
CloneNotSupportedExceptionif the object's class does not
     
*
               
support the {@code Cloneable} interface. Subclasses
     
*
               
that override the {@code clone} method can also
     
*
               
throw this exception to indicate that an instance cannot
     
*
               
be cloned.
     
*
 

     
*/

    
protected native Object clone() throws CloneNotSupportedException;

    
/**
     
* Returns a string representation of the object. In general, the
     
* {@code 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 recommended that all subclasses override this method.
     
* <p>
     
* The {@code toString} method for class {@code Object}
     
* returns a string consisting of the name of the class of which the
     
* object is an instance, the at-sign character `{@code @}', and
     
* the unsigned hexadecimal representation of the hash code of the
     
* object. In other words, this method returns a string equal to the
     
* value of:
     
* <blockquote>
     
* <pre>
     
* getClass().getName() + '@' + Integer.toHexString(hashCode())
     
* </pre></blockquote>
     
*
     
* @return
  
a string representation of the object.
     
*/

    
public String toString() {
        
return getClass().getName() + "@" + Integer.toHexString(hashCode());
    
}

    
/**
     
* Wakes up a single thread that is waiting on this object's
     
* monitor. If any threads are waiting on this object, one of them
     
* is chosen to be awakened. The choice is arbitrary and occurs at
     
* the discretion of the implementation. A thread waits on an object's
     
* monitor by calling one of the {@code wait} methods.
     
* <p>
     
* The awakened thread will not be able to proceed until the current
     
* thread relinquishes the lock on this object. The awakened thread will
     
* compete in the usual manner with any other threads that might be
     
* actively competing to synchronize on this object; for example, the
     
* awakened thread enjoys no reliable privilege or disadvantage in being
     
* the next thread to lock this object.
     
* <p>
     
* 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:
     
* <ul>
     
* <li>By executing a synchronized instance method of that object.
     
* <li>By executing the body of a {@code synchronized} statement
     
*that synchronizes on the object.
     
* <li>For objects of type {@code Class,} by executing a
     
*synchronized static method of that class.
     
* </ul>
     
* <p>
     
* Only one thread at a time can own an object's monitor.
     
*
     
* @throws
  
IllegalMonitorStateExceptionif the current thread is not
     
*
               
the owner of this object's monitor.
     
* @see
        
java.lang.Object#notifyAll()
     
* @see
        
java.lang.Object#wait()
     
*/

    
public final native void notify();

    
/**
     
* Wakes up all threads that are waiting on this object's monitor. A
     
* thread waits on an object's monitor by calling one of the
     
* {@code wait} methods.
     
* <p>
     
* The awakened threads will not be able to proceed until the current
     
* thread relinquishes the lock on this object. The awakened threads
     
* will compete in the usual manner with any other threads that might
     
* be actively competing to synchronize on this object; for example,
     
* the awakened threads enjoy no reliable privilege or disadvantage in
     
* being the next thread to lock this object.
     
* <p>
     
* This method should only be called by a thread that is the owner
     
* of this object's monitor. See the {@code notify} method for a
     
* description of the ways in which a thread can become the owner of
     
* a monitor.
     
*
     
* @throws
  
IllegalMonitorStateExceptionif the current thread is not
     
*
               
the owner of this object's monitor.
     
* @see
        
java.lang.Object#notify()
     
* @see
        
java.lang.Object#wait()
     
*/

    
public final native void notifyAll();

    
/**
     
* Causes the current thread to wait until either another thread invokes the
     
* {@link java.lang.Object#notify()} method or the
     
* {@link java.lang.Object#notifyAll()} method for this object, or a
     
* specified amount of time has elapsed.
     
* <p>
     
* The current thread must own this object's monitor.
     
* <p>
     
* This method causes the current thread (call it <var>T</var>) to
     
* place itself in the wait set for this object and then to relinquish
     
* any and all synchronization claims on this object. Thread <var>T</var>
     
* becomes disabled for thread scheduling purposes and lies dormant
     
* until one of four things happens:
     
* <ul>
     
* <li>Some other thread invokes the {@code notify} method for this
     
* object and thread <var>T</var> happens to be arbitrarily chosen as
     
* the thread to be awakened.
     
* <li>Some other thread invokes the {@code notifyAll} method for this
     
* object.
     
* <li>Some other thread {@linkplain Thread#interrupt() interrupts}
     
* thread <var>T</var>.
     
* <li>The specified amount of real time has elapsed, more or less.
  
If
     
* {@code timeout} is zero, however, then real time is not taken into
     
* consideration and the thread simply waits until notified.
     
* </ul>
     
* The thread <var>T</var> is then removed from the wait set for this
     
* object and re-enabled for thread scheduling. It then competes in the
     
* usual manner with other threads for the right to synchronize on the
     
* object; once it has gained control of the object, all its
     
* synchronization claims on the object are restored to the status quo
     
* ante - that is, to the situation as of the time that the {@code wait}
     
* method was invoked. Thread <var>T</var> then returns from the
     
* invocation of the {@code wait} method. Thus, on return from the
     
* {@code wait} method, the synchronization state of the object and of
     
* thread {@code T} is exactly as it was when the {@code wait} method
     
* was invoked.
     
* <p>
     
* A thread can also wake up without being notified, interrupted, or
     
* timing out, a so-called <i>spurious wakeup</i>.
  
While this will rarely
     
* occur in practice, applications must guard against it by testing for
     
* the condition that should have caused the thread to be awakened, and
     
* continuing to wait if the condition is not satisfied.
  
In other words,
     
* waits should always occur in loops, like this one:
     
* <pre>
     
*synchronized (obj) {
     
*
         
while (&lt;condition does not hold&gt;)
     
*
             
obj.wait(timeout);
     
*
         
... // Perform action appropriate to condition
     
*}
     
* </pre>
     
* (For more information on this topic, see Section 3.2.3 in Doug Lea's
     
* "Concurrent Programming in Java (Second Edition)" (Addison-Wesley,
     
* 2000), or Item 50 in Joshua Bloch's "Effective Java Programming
     
* Language Guide" (Addison-Wesley, 2001).
     
*
     
* <p>If the current thread is {@linkplain java.lang.Thread#interrupt()
     
* interrupted} by any thread before or while it is waiting, then an
     
* {@code InterruptedException} is thrown.
  
This exception is not
     
* thrown until the lock status of this object has been restored as
     
* described above.
     
*
     
* <p>
     
* Note that the {@code wait} method, as it places the current thread
     
* into the wait set for this object, unlocks only this object; any
     
* other objects on which the current thread may be synchronized remain
     
* locked while the thread waits.
     
* <p>
     
* This method should only be called by a thread that is the owner
     
* of this object's monitor. See the {@code notify} method for a
     
* description of the ways in which a thread can become the owner of
     
* a monitor.
     
*
     
* @param
      
timeout
   
the maximum time to wait in milliseconds.
     
* @throws
  
IllegalArgumentException
      
if the value of timeout is
     
*
               
negative.
     
* @throws
  
IllegalMonitorStateExceptionif the current thread is not
     
*
               
the owner of the object's monitor.
     
* @throws
  
InterruptedException if any thread interrupted the
     
*
             
current thread before or while the current thread
     
*
             
was waiting for a notification.
  
The <i>interrupted
     
*
             
status</i> of the current thread is cleared when
     
*
             
this exception is thrown.
     
* @see
        
java.lang.Object#notify()
     
* @see
        
java.lang.Object#notifyAll()
     
*/

    
public final native void wait(long timeout) throws InterruptedException;

    
/**
     
* Causes the current thread to wait until another thread invokes the
     
* {@link java.lang.Object#notify()} method or the
     
* {@link java.lang.Object#notifyAll()} method for this object, or
     
* some other thread interrupts the current thread, or a certain
     
* amount of real time has elapsed.
     
* <p>
     
* This method is similar to the {@code wait} method of one
     
* argument, but it allows finer control over the amount of time to
     
* wait for a notification before giving up. The amount of real time,
     
* measured in nanoseconds, is given by:
     
* <blockquote>
     
* <pre>
     
* 1000000*timeout+nanos</pre></blockquote>
     
* <p>
     
* In all other respects, this method does the same thing as the
     
* method {@link #wait(long)} of one argument. In particular,
     
* {@code wait(0, 0)} means the same thing as {@code wait(0)}.
     
* <p>
     
* 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:
     
* <ul>
     
* <li>Another thread notifies threads waiting on this object's monitor
     
*to wake up either through a call to the {@code notify} method
     
*or the {@code notifyAll} method.
     
* <li>The timeout period, specified by {@code timeout}
     
*milliseconds plus {@code nanos} nanoseconds arguments, has
     
*elapsed.
     
* </ul>
     
* <p>
     
* The thread then waits until it can re-obtain ownership of the
     
* monitor and resumes execution.
     
* <p>
     
* As in the one argument version, interrupts and spurious wakeups are
     
* possible, and this method should always be used in a loop:
     
* <pre>
     
*synchronized (obj) {
     
*
         
while (&lt;condition does not hold&gt;)
     
*
             
obj.wait(timeout, nanos);
     
*
         
... // Perform action appropriate to condition
     
*}
     
* </pre>
     
* This method should only be called by a thread that is the owner
     
* of this object's monitor. See the {@code notify} method for a
     
* description of the ways in which a thread can become the owner of
     
* a monitor.
     
*
     
* @param
      
timeout
   
the maximum time to wait in milliseconds.
     
* @param
      
nanosadditional time, in nanoseconds range
     
*
                       
0-999999.
     
* @throws
  
IllegalArgumentException
      
if the value of timeout is
     
*
                      
negative or the value of nanos is
     
*
                      
not in the range 0-999999.
     
* @throws
  
IllegalMonitorStateExceptionif the current thread is not
     
*
               
the owner of this object's monitor.
     
* @throws
  
InterruptedException if any thread interrupted the
     
*
             
current thread before or while the current thread
     
*
             
was waiting for a notification.
  
The <i>interrupted
     
*
             
status</i> of the current thread is cleared when
     
*
             
this exception is thrown.
     
*/

    
public final void wait(long timeout, int nanos) throws InterruptedException {
        
if (timeout < 0) {
            
throw new IllegalArgumentException("timeout value is negative");
        
}

        
if (nanos < 0 || nanos > 999999) {
            
throw new IllegalArgumentException(
                                
"nanosecond timeout value out of range");
        
}

        
if (nanos > 0) {
            
timeout++;
        
}

        
wait(timeout);
    
}

    
/**
     
* Causes the current thread to wait until another thread invokes the
     
* {@link java.lang.Object#notify()} method or the
     
* {@link java.lang.Object#notifyAll()} method for this object.
     
* In other words, this method behaves exactly as if it simply
     
* performs the call {@code wait(0)}.
     
* <p>
     
* 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 {@code notify} method or the
     
* {@code notifyAll} method. The thread then waits until it can
     
* re-obtain ownership of the monitor and resumes execution.
     
* <p>
     
* As in the one argument version, interrupts and spurious wakeups are
     
* possible, and this method should always be used in a loop:
     
* <pre>
     
*synchronized (obj) {
     
*
         
while (&lt;condition does not hold&gt;)
     
*
             
obj.wait();
     
*
         
... // Perform action appropriate to condition
     
*}
     
* </pre>
     
* This method should only be called by a thread that is the owner
     
* of this object's monitor. See the {@code notify} method for a
     
* description of the ways in which a thread can become the owner of
     
* a monitor.
     
*
     
* @throws
  
IllegalMonitorStateExceptionif the current thread is not
     
*
               
the owner of the object's monitor.
     
* @throws
  
InterruptedException if any thread interrupted the
     
*
             
current thread before or while the current thread
     
*
             
was waiting for a notification.
  
The <i>interrupted
     
*
             
status</i> of the current thread is cleared when
     
*
             
this exception is thrown.
     
* @see
        
java.lang.Object#notify()
     
* @see
        
java.lang.Object#notifyAll()
     
*/

    
public final void wait() throws InterruptedException {
        
wait(0);
    
}

    
/**
     
* Called by the garbage collector on an object when garbage collection
     
* determines that there are no more references to the object.
     
* A subclass overrides the {@code finalize} method to dispose of
     
* system resources or to perform other cleanup.
     
* <p>
     
* The general contract of {@code finalize} is that it is invoked
     
* if and when the Java&trade; virtual
     
* machine has determined that there is no longer any
     
* means by which this object can be accessed by any thread that has
     
* not yet died, except as a result of an action taken by the
     
* finalization of some other object or class which is ready to be
     
* finalized. The {@code finalize} method may take any action, including
     
* making this object available again to other threads; the usual purpose
     
* of {@code finalize}, however, is to perform cleanup actions before
     
* the object is irrevocably discarded. For example, the finalize method
     
* for an object that represents an input/output connection might perform
     
* explicit I/O transactions to break the connection before the object is
     
* permanently discarded.
     
* <p>
     
* The {@code finalize} method of class {@code Object} performs no
     
* special action; it simply returns normally. Subclasses of
     
* {@code Object} may override this definition.
     
* <p>
     
* The Java programming language does not guarantee which thread will
     
* invoke the {@code finalize} method for any given object. It is
     
* guaranteed, however, that the thread that invokes finalize will not
     
* be holding any user-visible synchronization locks when finalize is
     
* invoked. If an uncaught exception is thrown by the finalize method,
     
* the exception is ignored and finalization of that object terminates.
     
* <p>
     
* After the {@code finalize} method has been invoked for an object, no
     
* further action is taken until the Java virtual machine has again
     
* determined that there is no longer any means by which this object can
     
* be accessed by any thread that has not yet died, including possible
     
* actions by other objects or classes which are ready to be finalized,
     
* at which point the object may be discarded.
     
* <p>
     
* The {@code finalize} method is never invoked more than once by a Java
     
* virtual machine for any given object.
     
* <p>
     
* Any exception thrown by the {@code finalize} method causes
     
* the finalization of this object to be halted, but is otherwise
     
* ignored.
     
*
     
* @throws Throwable the {@code Exception} raised by this method
     
*
 

     
*
 

     
* @jls 12.6 Finalization of Class Instances
     
*/

    
protected void finalize() throws Throwable { }
}