Key difference between final, finally, finalize in java
final in java:
final is a keyword applicable for variables methods and
classes.
final variables:
Variables
declared with final keyword are
called as final variables. In java if a variable is declared as final then its
value can’t be changed during program execution.
when
you don’t want to change the value of variable then declare them as final.
final variables has to be initialized before use.
syntax:
final
<datatype> <var_name> = value;
final
int x=100;
final methods:
In java
if any method is declared with final keyword then they are called as final method. when ever we declare any method as final then we can’t
override these methods in the sub classes.
class
Demo{
void m1{
System. out. println( "m1 method of
demo class");
}
final
void m2{
System. out. println( "m2 method of
demo class");
System. out. println( "final method of
demo class");
}
}
In above example we declared m2 as final
hence we can’t override this method in
the sub classes of Demo class.
final classes
classes
declared with final keyword are called as final
classes. These class can’t be inherited.
A final class can’t be declared as
abstract class.
final class
Demosuper{
void
m1{
System. out. println( "m1 method of
demo super class");
}
void
m2{
System. out. println( "m2 method of
demo super class");
}
}
The
above class is declared as final class
thence we can’t create the sub class for Demosuper class. Hence we cant cant
inherit these classes.
finally:
finally is a keyword in java that is
applicable for blocks.
whenever
we want anything to execute independent of whether exception is raised or not
then we go for finally.
finally{
......
...... // some statements.
......
}
finalize:
This is
a method in java programming language. This method belongs Object Class which
is the super class of all classes in java.
Before
the object is garbage collected by JVM finalize
method is called.
Answer these questions….
Can we extend final class in java?
What is the basic use of finalize method in java.
Who calls finalize method in java programming language.
When finalize method is called.
Is finalize guaranteed to be called.
What is the main purpose of final keyword in java?
What is final finally finally in java?
What is the main use of finally in java?
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