This document contains information about the "this" keyword in Java and garbage collection. It discusses that the "this" keyword refers to current class instance variables and can be used to resolve ambiguity between instance variables and parameters. It provides examples of when to use "this" including to access class variables, pass as a method argument, implicitly invoke current class methods, and return the current object. The document also defines garbage collection as the process of reclaiming unused memory by destroying unused objects, explains it is performed automatically in Java, and lists ways an object can become unreferenced like nulling a reference or assigning a reference to another object.

1. NAME- SUCHANDA BANERJEE
ROLL NO.- 10800120085
BATCH- B
SEM- 5TH
TOPIC- ‘THIS’ KEYWORD AND GARBAGE COLLECTION
ASANSOL ENGINEERING COLLEGE

2. Java :
this keyword: to refer current class instance variable.
The this keyword can be used to refer current class instance
variable. If there is ambiguity between the instance variables and
parameters, this keyword resolves the problem of ambiguity.

3. When To Use ‘this’ In Java?
In Java the term ‘this’ has the following uses:
 The reference ‘this’ is used to access the class instance variable.
 You can even pass ‘this’ as an argument in the method call.
 ‘this’ can also be used to implicitly invoke the current class method.
 If you want to return the current object from the method, then use
‘this’.
 If you want to invoke the current class constructor, ‘this’ can be used.
 The constructor can also have ‘this’ as an argument.

4. Garbage Collection:
In java, garbage means unreferenced objects.
 Garbage Collection is process of reclaiming the
runtime unused memory automatically. In other
words, it is a way to destroy the unused objects.
 To do so, we were using free() function in C
language and delete() in C++. But, in java it is
performed automatically. So, java provides better
memory management.

5. Advantage 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.

6. How can an object be
unreferenced?
 1) By nulling a reference:
Employee e=new Employee();
e=null;
 2) By assigning a reference to another:
Employee e1=new Employee();
Employee e2=new Employee();
e1=e2; //now the first object referred by e1 is available for garbage collection
 3) By anonymous object:
new Employee();