Java Reserved Keywords

12 May 2025 | 3 min read

Keywords are reserved words in Java that serve as a code key. These words can't be used for anything else because they're predefined. They can't be used as a variable name, object name, or any other identifier. There are 51 reserved terms or keywords in Java.

List of Java Reserved Keywords

Keyword	Description
abstract	Indicates the class or method that follows this keyword is abstract and that will have to be implemented by a subclass.
assert	Assert keyword helps the programmer to declare assertions or assumptions in a program. If an assertion is true, program progresses normally otherwise the AssertionError is thrown at runtime and program aborts.
boolean	Defines two Boolean values, true or false, 0 and 1.
break	Used to break out of loops or iterative constructs.
byte	Data type capable of holding 8-bit data.
case	Marks blocks of text (cases) in a Switch statement.
catch	Used to catch exceptions generated in the try block.
char	Data type able to hold unsigned 16-bit Unicode characters.
class	Used to declare a new class.
continue	It helps to take control outside the loop and continue to the next iteration.
default	Defines the "block of code" that will execute by default in a Switch statement.
do	Starting keyword for "do-while" loop.
double	Data type holding 64-bit numbers (floating-point).
else	Defines else part in the 'if' statements.
enum	Used to declare enumerations in Java.
extends	Indicates inheritance. A class is derived or inherited from another class.
final	Defines a variable which will hold constant values or a method that cannot be overridden.
finally	Defines the finally block that executes after the try-catch block irrespective of whether the exception was caught or not.
float	Data type able to hold 32-bit floating-point values.
for	Indicates the start of a 'for' loop.
if	Start of 'if' statement.
implements	Indicates that a class implements an interface.
import	Used to include or reference other packages/classes into the program.
instanceOf	Used to check if the given object is an instance of another class.
int	Data type to hold a 32-bit integer value.
interface	Used for declaring an interface.
long	Data type holding 64-bit integer values.
native	Used to indicate native code (platform-specific).
new	Operator to create a new object.
null	Indicates null reference.
package	Keyword to declare Java package.
private	Indicates private access specified which means a variable or method can be accessed only by the class in which it is declared.
protected	This keyword indicates a protected access specifier. When a variable or method is protected then that variable or method can be accessed only by the class they are declared in, its subclass, and other classes in the same package.
public	The public keyword is used to indicate public access specifier. A variable, method, classes, interfaces declared as public can be accessed throughput the application.
return	Return is used to send back the value of a method to the calling method. It also is used to return the control to the calling method.
short	Data type holding 16-bit integer number values.
static	The static keyword indicates the method or a variable is static and cannot be instantiated.
strictfp	The keyword strictfp restricts the rounding and precision of floating point values calculation. It ensures portability.
super	Indicates base or superclass of the class.
switch	Indicates a Switch statement that tests a condition and executes multiple cases depending on the test value.
synchronized	Indicates synchronized sections for multithreaded code like critical section.
this	The keyword 'this' indicates the current object.
throw	Throws an exception.
throws	This indicates the exception that can be thrown by a method.
transient	Specifies transient variable that is not part of the persistent state of an object.
try	Try keywords start a block that contains code that might raise exceptions.
void	Indicates no return value.
volatile	Used to define variables that are not stored in Main Memory. They can be changed asynchronously.
while	Keyword while starts a while loop.
const	The 'const' keyword is no more supported in Java
goto	The 'goto' keyword is no more supported in Java
true, false and null	The words "true, false, null" are literals. Still, we cannot use them as identifiers in the program.