Keyword is a reserved word in programming language which is predefined. Because it has a special meaning. keyword cannot be used as name for class, method and function. Keyword cannot be used as a identifier also. There are few keyword in java as follows:
abstract: abstract keyword is used to declare class, method. If a class is declared as abstract then we cannot create the object of that class. Abstract keyword is used to declare a method without providing the implementation.
assert : assert keyword is used to make assertion. It is used to test the assumption about your program.
boolean : boolean keyword is used to store boolean value that is true or false. This keyword is also used to declare a method that return a value of type boolean.
break : Used to come out from the program execution immediately following the enclosing statement block.
case : case keyword is used in switch case to create individual cases.
catch : This keyword is used to handle the exception that occurred in the program preceding by try block.
class : This keyword is used to defined the implementation of particular object .
const : It is a keyword in java but not used hence it has no function.
continue : continue is a keyword that is used to resume program execution to the end of the loop body.
default : default keyword is used in the switch statement, if no matches found in switch cases, then default statement is executed.
do : do keyword is used with while loop, which execute the block of code associated with the loop.
else : else keyword is used with if to create if-else statement that check the boolean expression. It return true when the statement within if is executed, return false when statement within else will executed.
enum : enum keyword is used to declare enumerated type.
final : Used to defined a class, method and variable. If a class defined as final it cannot be inherited by subclass, if a variable is defined as final variable it cannot be changed and final method cannot be overridden..
goto : goto is a reserved word in java but not used hence it has no function.
new : used to create an instance of class.
public : is used to declare class, method and field ; public class, method and field can be accessed by any class.
void : void keyword is used to declare a method that does not return any value.
Recommend the tutorial