Java Keywords

Java keywords are commonly referred to as reserved words. They serve as crucial identifiers within the code. Java designates these specific words to have predefined meanings, preventing them from being utilized as variable, object, or class names.

Example


//Program of Java keywords  

public class Main {    

    public static void main(String[] args)    

    {    

        //Using int keyword  

        int a=10;  

        int b=20;  

        //Using if-else keywords  

        if(a<b){  

            System.out.println(a+" is less than "+b);  

        } 

     else {  

            System.out.println(a+" is greater than "+b);  

        }  

    }    

}

Output:

Output


10 is less than 20

List of Java Keywords

Below is a compilation of reserved words or keywords in Java:

Category	Keywords	Usage
Data Type	boolean	Java boolean keyword is used to declare a variable as a boolean type. It can hold True and False values only.
`byte`	Java byte keyword is used to declare a variable that can hold 8-bit data values.
`char`	Java char keyword is used to declare a variable that can hold unsigned 16-bit Unicode characters.
double	Java double keyword is used to declare a variable that can hold 64-bit floating-point number.
float	Java float keyword is used to declare a variable that can hold a 32-bit floating-point number.
`int`	Java int keyword is used to declare a variable that can hold a 32-bit signed integer.
`long`	Java long keyword is used to declare a variable that can hold a 64-bit integer.
short	Java short keyword is used to declare a variable that can hold a 16-bit integer.
Control Flow	break	Java break keyword is used to break the loop or switch statement. It breaks the current flow of the program at specified conditions.
`case`	Java case keyword is used with the switch statements to mark blocks of text.
continue	The Java continue keyword is used to continue the loop. It continues the current flow of the program and skips the remaining code at the specified condition.
default	Java default keyword is used to specify the default block of code in a switch statement.
`do`	The Java do keyword is used in the control statement to declare a loop. It can iterate a part of the program several times.
`else`	Java else keyword is used to indicate the alternative branches in an if statement.
`for`	Java for keyword is used to start a for loop. It is used to execute a set of instructions/functions repeatedly when some condition becomes true. If the number of iteration is fixed, it is recommended to use for loop.
`if`	Java if keyword tests the condition. It executes the if block if the condition is true.
return	Java return keyword is used to return from a method when its execution is complete.
switch	The Java switch keyword contains a switch statement that executes code based on test value. The switch statement tests the equality of a variable against multiple values.
while
Modifiers	abstract	Java abstract keyword is used to declare an abstract class. An abstract class can provide the implementation of the interface. It can have abstract and non-abstract methods.
final	Java final keyword is used to indicate that a variable holds a constant value. It is used with a variable. It is used to restrict the user from updating the value of the variable.
native	Java native keyword is used to specify that a method is implemented in native code using JNI (Java Native Interface).
private	Java private keyword is an access modifier. It is used to indicate that a method or variable may be accessed only in the class in which it is declared.
protected	The protected keyword is an access modifier. It can be accessible within the package and outside the package but through inheritance only. It cannot be applied to the class.
public	Java public keyword is an access modifier. It is used to indicate that an item is accessible anywhere. It has the widest scope among all other modifiers.
static	Java static keyword is used to indicate that a variable or method is a class method. The static keyword in Java is mainly used for memory management.
strictfp	Java strictfp is used to restrict the floating-point calculations to ensure portability.
synchronized	Java synchronized keyword is used to specify the critical sections or methods in multithreaded code.
transient	Java transient keyword is used in serialization. If you define any data member as transient, it will not be serialized.
volatile	Java volatile keyword is used to indicate that a variable may change asynchronously.
Class Related	class	Java class keyword is used to declare a class.
extends	Java extends keyword is used to indicate that a class is derived from another class or interface.
super	Java super keyword is a reference variable that is used to refer to parent class objects. It can be used to invoke the immediate parent class method.
implements	Java implements keyword is used to implement an interface.
interface	Java interface keyword is used to declare an interface. It can have only abstract methods.
`new`	Java new keyword is used to create new objects.
`this`	Java this keyword can be used to refer the current object in a method or constructor.
Exception Handling	try	Java try keyword is used to start a block of code that will be tested for exceptions. The try block must be followed by either catch or finally block.
catch	Java catch keyword is used to catch the exceptions generated by try statements. It must be used after the try block only.
finally	Java finally keyword indicates a block of code in a try-catch structure. This block is always executed whether an exception is handled or not.
throw	The Java throw keyword is used to explicitly throw an exception. The throw keyword is mainly used to throw custom exceptions. It is followed by an instance.
throws	The Java throws keyword is used to declare an exception. Checked exceptions can be propagated with throws.
Package Related	import	Java import keyword makes classes and interfaces available and accessible to the current source code.
package	Java package keyword is used to declare a Java package that includes the classes.
Others	assert	Assert describes a predicate placed in a Java program to indicate that the developer thinks that the predicate is always true at that place.
`enum`	Java enum keyword is used to define a fixed set of constants. Enum constructors are always private or default.
`instanceof`	Java instanceof keyword is used to test whether the object is an instance of the specified class or implements an interface.
`null`	Java null keyword is used to indicate that a reference does not refer to anything. It removes the garbage value.
`void`	Java void keyword is used to specify that a method does not have a return value.

The keywords const and goto are reserved, even though they are not currently used. true , false , and null might seem like keywords, but they are actually literals; we cannot use them as identifiers in your programs.

Example

List of Java Keywords

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