RESERVED WORDS IN JAVA
Keyword Contextual Description
abstract Used
in a class definition to specify that a class is not to be instantiated, but
rather inherited by other classes
boolean Refers to an expression or
variable that can have only a true or false value
break Terminates processing of a switch statement or loop
byte A sequence of eight
bits
case Used in a switch statement to specify a match for
the statement's expression
catch Used to specify the
actions to be taken when an exception occurs (see throw, try)
char Declares objects whose
values are characters
class Construct new types to
describe data and operations
continue Used in a loop statement to
transfer control to the beginning of the loop
default Used in a switch statement to handle expression
values not specified using case
do Marks the beginning
of a do-while statement
double Declares objects whose
values are double precision real numbers
else Used as the alternative
action of an if statement
extends Used to specify that a
subclass inherits the methods of a superclass
final An entity that is
defined once and cannot be changed or derived from later
finally Executes
a block of statements regardless of whether a Java Exception, or run time
error, occurred in a block defined previously by the "try"
keyword
float Declares a primitive
data type whose values are single precision real numbers
for Marks the beginning
of a for statement
if Marks the beginning
of an if statement
implements Optionally
included in the class declaration to specify any interfaces that are
implemented by the current class
import Used
at the beginning of a source file that can specify classes or entire packages
to be referred to later without including their package names in the reference
instanceof tests
whether the run-time type of its first argument is assignment compatible with
its second argument
int Declares objects
whose values are integer numbers
interface used to define a collection of
method definitions and constant values
long Used to declare a
primitive data type with values that range from
new Allocates memory
dynamically at run-time
package A group of types
private Declares class members that are inaccessible
from outside of the class
protected Declares class members that are private,
except to derived classes
public Declares class members that can be accessed
outside of the class
return Terminates a function,
usually returning the value of some expression
short Used to declare 16-bit
integer numbers
static Declares objects whose
lifetime is the duration of the program
super Used to access members of
a class inherited by the class in which it appears
switch Marks the beginning of a
switch statement
synchronized When
applied to a method or code block, guarantees that at most one thread at a time
executes that code
this Used with a class member to unambiguously access
other members of the class
throw Used to generate an
exception (see catch, try)
throws Used
in method declarations that specify which exceptions are not handled within the
method but rather passed to the next higher level of the program
try Used to mark the
beginning of a block containing exception handlers (see catch)
void Used to indicate the
absence of any type (for a function or parameter list)
while Marks
the beginning of a while statement,
as well as the end of a do-while
statement