Constant is an identifier whose value can not be changed during program execution.
In java if you want to make the identifier as constant so you have to use the final keyword. Final is a keyword which is very important foe three things. And they are variable, method , class.
If we want to make something non changeable during program execution so for that we have to make it as final.
Syntax.Final data type v1=val1, v2=val2.. ; Example final int a=20; a=a+30; //invalid
class ScopeError { public static void main(String args[]) { int bar=1; { int bar=2; //compile time eroor } } }O/P
g:\java>javac ScopeError.java ScopeError.java:7: Error: variable bar is already defined in method main(String[]) int bar=2 1 error