There are few keywords in Java programming language. Remember, we cannot use these keywords as identifiers in the program.

Java Keywords

There are few keywords in Java programming language. Remember, we cannot use these keywords as identifiers in the program. The keywords const and goto are reserved though, they are not being currently used.  
The brief description of each one of the keyword is given below.

abstract
When a class is not to be instantiated, use abstract keyword but rather extended by other classes. This keyword is used to in a method declaration to declare a method without providing the implementation. 

assert 
It is used to define an assert statement. Any boolean condition in a program is declared with the help of assert statement. The condition is checked at runtime if the program is running with assertions . If the condition is false, the Java runtime system throws an AssertionError.

boolean
This keyword is used to pertain to an expression or variable that can have only a true or false value. 

byte
This is 8-bit integer. This keyword is used to declare an expression, method return value, or variable of type byte.

case
This keyword is used to defines a group of statements. The value defined by the enclosing switch statement should match with the specified value.

catch
This keyword is used to handle the exceptions that occur in a program preceding try keyword. When the class of the thrown exception is assignment compatible with the exception class declared by the catch clause then only the code is executed.

char
This Java keyword is used to declare an expression, method return value, or variable of type character.

class
This keyword is used to define the implementation of a particular kind of object.  

const 
This keyword has been deprecated from Java programming language.

continue
This keyword is used for the continuation of the program at the end of the current loop body. 

default
If the value defined by the enclosing switch statement does not match any value specified by a case keyword in the switch statement, default keyword is used to define a group of statements to begin the execution.

do
Used to declare a loop that will iterate a block of statements. The loop's exit condition is specified with the while keyword. The loop will execute once before evaluating the exit condition.

double
A 64-bit floating point value. A Java keyword used to declare an expression, method return value, or variable of type double-precision floating point number.

else
This keyword is used to test the condition. It is used to define a statement or block of statements that are executed in the case that the test condition specified by the if keyword evaluates to false.

enum 
Enumerations extend the base class Enum.This Java keyword is used to declare an enumerated type. 

extends
 To specify the superclass in a class declaration, extends keyword is used. It is also used in an interface declaration to specify one or more superinterfaces.

final
It is used to define an entity once that cannot be altered nor inherited later. Moreover, a final class cannot be subclassed, a final method cannot be overridden, and a final variable can occur at most once as a left-hand expression. All methods in a final class are implicitly final.

finally
This keyword is used when the finally block is executed after the execution exits the try block and any associated catch clauses regardless of whether an exception was thrown or caught.

break
Used to resume program execution at the statement immediately following the current enclosing block or statement. If followed by a label, the program resumes execution at the statement immediately following the enclosing labeled statement or block.

strictfp
To get the precise results in Floating point calculations use strictfp keyword regardless of any operating system and hardware platform.