Java Keywords

Keyword

Description

abstract

An abstract class, a non-access modifier used for classes and methods, cannot be instantiated directly; it must be inherited by another class. Abstract methods within an abstract class lack a body and must be implemented by subclasses

assert

For the purpose of debugging.

boolean

A boolean data type, capable of storing only true or false values.

break

Terminates the execution of a loop or a switch block.

byte

A byte data type, capable of storing whole numbers within the range of -128 to 127.

case

Identifies a block of code within switch statements.

catch

Handles exceptions thrown by try statements.

char

A char data type, utilized for storing a single character.

class

Declares a class.

continue

Proceeds to the next iteration of a loop.

const

Specifies a constant. Deprecated; use final instead.

default

Specifies the default block of code within a switch statement.

do

Employed in conjunction with while to construct a do-while loop.

double 

A double data type, capable of storing decimal numbers ranging from 1.7e−308 to 1.7e+308.

else

Employed in conditional statements.

enum

Declares an enumerated (unchangeable) type.

exports

Exports a package within a module. Introduced in Java 9.

extends

Indicates inheritance from another class; extends a class.

final

A non-access modifier applied to classes, attributes, and methods, rendering them unmodifiable (preventing inheritance or overriding).

finally

Utilized with exceptions, a block of code that executes regardless of whether an exception occurs or not.

float

A float data type, capable of storing decimal numbers ranging from 3.4e−038 to 3.4e+038.

for

Generate a for loop.

go to

Deprecated and non-functional.

if

Creates a conditional statement.

implements

Implements an interface.

import

Utilized to import a package, class, or interface.

instance of

Verifies whether an object is an instance of a particular class or interface.

int

An int data type, capable of storing whole numbers within the range of -2147483648 to 2147483647.

interface

Utilized to declare an interface, a special type of class that exclusively contains abstract methods.

long

A long data type, capable of storing whole numbers within the range of -9223372036854775808 to 9223372036854775807.

module

Specifies a module declaration. Introduced in Java 9.

native

Specifies that a method is not implemented in the current Java source file but in another language.

new

Instantiates new objects.

package

Defines a package.

private

An access modifier applied to attributes, methods, and constructors, restricting their accessibility to only within the declared class.

protected

An access modifier applied to attributes, methods, and constructors, allowing access within the same package and by subclasses.

public

An access modifier applied to classes, attributes, methods, and constructors, granting accessibility to any other class.

requires

Defines required libraries within a module. Introduced in Java 9.

return

Concludes the execution of a method, optionally returning a value from the method.

short

A short data type, capable of storing whole numbers within the range of -32768 to 32767.

static

A non-access modifier applied to methods and attributes. Static methods/attributes can be accessed without instantiating a class.

strictfp

Control the precision and rounding of floating-point calculations.

super

Refers to superclass (parent) objects.

switch

Chooses one of multiple code blocks to execute.

synchronized

A non-access modifier, specifying that methods can only be accessed by one thread at a time.

this

Refers to the current object within a method or constructor.

throw

Defines a custom error.

throws

Specifies which exceptions may be thrown by a method.

transient

A non-access modifier indicating that an attribute is not part of an object’s persistent state.

try

Constructs a try…catch statement.

var

Declares a variable. Introduced in Java 10.

void

Specifies that a method should not have a return value.

volatile

Indicates that an attribute is not cached thread-locally and is consistently read from the “main memory”.

while

Generates a while loop.