Keyword

Purpose

boolean

declares a boolean variable or return type

byte

declares a byte variable or return type

char

declares a character variable or return type

double

declares a double variable or return type

float

declares a floating point variable or return type

short

declares a short integer variable or return type

void

declare that a method does not return a value

int

declares an integer variable or return type

long

declares a long integer variable or return type

while

begins a while loop

for

begins a for loop

do

begins a do while loop

switch

tests for the truth of various possible cases

break

prematurely exits a loop

continue

prematurely return to the beginning of a loop

case

one case in a switch statement

default

default action for a switch statement

if

execute statements if the condition is true

else

signals the code to be executed if an if statement is not true

try

attempt an operation that may throw an exception

catch

handle an exception

finally

declares a block of code guaranteed to be executed

class

signals the beginning of a class definition

abstract

declares that a class or method is abstract

extends

specifies the class which this class is a subclass of

final

declares that a class may not be subclassed or that a field or method may not be overridden

implements

declares that this class implements the given interface

import

permit access to a class or group of classes in a package

instanceof

tests whether an object is an instanceof a class

interface

signals the beginning of an interface definition

native

declares that a method is implemented in native code

new

allocates a new object

package

defines the package in which this source code file belongs

private

declares a method or member variable to be private

protected

declares a class, method or member variable to be protected

public

declares a class, method or member variable to be public

return

returns a value from a method

static

declares that a field or a method belongs to a class rather than an object

super

a reference to the parent of the current object

synchronized

Indicates that a section of code is not thread-safe

this

a reference to the current object

throw

throw an exception

throws

declares the exceptions thrown by a method

transient

This field should not be serialized

volatile

Warns the compiler that a variable changes asynchronously