Bachelor of Computer Applications: Garbage Collection

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<b><span style="font-family: "Calibri","sans-serif"; mso-bidi-font-family: Arial;"><span style="color: #0b5394;">Garbage Collection</span></span></b></h2>
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<li><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;"><span style="font-family: 'Times New Roman'; font-size: 7pt;">  </span></span><span style="font-family: "Calibri","sans-serif"; mso-bidi-font-family: Arial;">Objects are dynamically allocated by using the <b>new</b>
operator.</span></li>
<li><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-fareast-font-family: Wingdings;"><span style="font-family: 'Times New Roman'; font-size: 7pt;"> </span></span><span style="font-family: "Calibri","sans-serif"; mso-bidi-font-family: Arial;">In some languages, such as C++, dynamically
allocated objects must be manually released by use of a <b>delete</b> operator.</span></li>
<li><span style="font-family: Wingdings; mso-bidi-font-family: Wingdings; mso-bidi-font-style: italic; mso-fareast-font-family: Wingdings;"><span style="font-family: 'Times New Roman'; font-size: 7pt;"> </span></span><span style="font-family: "Calibri","sans-serif"; mso-bidi-font-family: Arial;">Java
handles deallocation for you automatically. The technique that accomplishes
this is called <b><i>garbage collection</i></b><i>.</i></span></li>
<li>When no references to an object exist, that object
is assumed to be no longer needed, and the memory occupied by the object can be
reclaimed.</li>
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<span style="background-color: white;">Garbage collection (GC) is a form of
automatic <span style="text-decoration: none;">memory
management</span>. The garbage collector, or just collector,
attempts to reclaim <a href="http://en.wikipedia.org/wiki/Garbage_(computer_science)"><span style="text-decoration: none;">garbage</span></a>,
or memory occupied by <span style="text-decoration: none;">objects</span> that
are no longer in use by the <span style="text-decoration: none;">program</span>.
Garbage collection was invented by <span style="text-decoration: none;">John McCarthy</span> around
1959 to solve problems in <span style="text-decoration: none;">Lisp</span>.<span style="color: #1f0707; font-size: 10.5pt;"><o:p></o:p></span></span></div>
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<span style="background-color: white;"><span style="color: #d78787; text-decoration: none;"></span><span style="color: #1f0707;">Garbage collection is
often portrayed as the opposite of</span><span style="color: #3d85c6;"> <a href="http://en.wikipedia.org/wiki/Manual_memory_management"><span style="text-decoration: none;">manual memory
management</span></a></span><span style="color: #1f0707;">, which requires the programmer to specify which objects
to deallocate and return to the memory system. However, many systems use a
combination of approaches, including other techniques such as </span>stack allocation<span style="color: #1f0707;"> and </span><span style="text-decoration: none;">region inference</span><span style="color: #1f0707;">.<o:p></o:p></span></span></div>
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<span style="background-color: white;">Resources other than memory, such as <span style="text-decoration: none;">network sockets</span>, database <span style="text-decoration: none;">handles</span>, user interactionwindows,
and file and device descriptors, are not typically handled by garbage
collection. Methods used to manage such resources, particularly <span style="text-decoration: none;">destructors</span>,
may suffice to manage memory as well, leaving no need for GC. Some GC systems
allow such other resources to be associated with a region of memory that, when
collected, causes the other resource to be reclaimed; this is called <span style="text-decoration: none;">finalization</span>. Finalization
may introduce complications limiting its usability, such as intolerable latency
between disuse and reclaim of especially limited resources, or a lack of control
over which thread performs the work of reclaiming.<span style="color: #1f0707;"><o:p></o:p></span></span></div>
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Garbage Collection in Java

Garbage Collection Objects are dynamically allocated by using the new operator. In some languages, such as C++, dynamically...