nice and excellent ppt

1. Garbage Collection
 new keyword is used to allocate
memory in heap at runtime for the
objects. Constructor is called at the
time of object creation automatically.
 We were using free() function in C
language and delete() in C++ to de-
allocate memory at runtime. But, in
java it is performed automatically. So,
java provides better memory
management.
 In Java, memory de-allocation

2. Garbage Collection
 In Java, garbage means unreferenced
objects.
 When to perform memory de-
allocation? 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 de-
allocated.
 The garbage collector (java program)
finds these unused objects and
deletes them to free up memory.

3. Garbage Collection
 Garbage collection occurs sporadically
(irregular intervals) during the
execution of the program.
 The main objective of Garbage
collector is to free heap memory by
destroying unused objects.
 To make objects as unreferenced,
assign null to objects.
 Eg:
Employee e=new Employee(); e=null;

4. Garbage Collection
 System.gc() or
Runtime.getRuntime().gc(), these two
methods are used to call garbage
collector in your Java program.
 Advantages of garbage collection
◦ It makes java memory efficient because
garbage collector removes the
unreferenced objects from heap memory.
◦ It is automatically done by the garbage
collector (a part of JVM) so we don't need
to make extra efforts.