Java keywords is also known as reserved keywords, they are words which are predfined and every keyword has a perticular meaning and usage, they cannot be used as a variable or object name or class name.
List of Java Keywords:
boolean: Java boolean is the used to declare variable of boolean data type, which holds True or False.
abstract: abstract is used to declare an abstract class. An abstract class can provide the implementation of Interface.
break: This keyword is used in loops to break the flow, it is also used with switch statements.
case: Java case keyword is used with the switch statements to mark blocks of text.
byte: Java byte keyword is used to declare a variable that can hold 8-bit data values.
catch: Java catch keyword is used to catch the exceptions generated by try statements. It must be used after the try block only.
char: Java char keyword is used to declare a variable that can hold unsigned 16-bit Unicode characters.
continue: 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.
class: Java class keyword is used to declare a class.
default: Java default keyword is used to specify the default block of code in a switch statement.
do: Java do keyword is used in the control statement to declare a loop. It can iterate a part of the program several times.
double: Java double keyword is used to declare a variable that can hold 64-bit floating-point number.
else: Java else keyword is used to indicate the alternative branches in an if statement.
enum: Java enum keyword is used to define a fixed set of constants. Enum constructors are always private or default.
extends: Java extends keyword is used to indicate that a class is derived from another class or interface.
final: final keyword is used to restrict user from updating the variable value making it a constant.
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.
float: Java float keyword is used to declare a variable that can hold a 32-bit floating-point number.
implements: Java implements keyword is used to implement an interface.
instanceof: Java instanceof keyword is used to test whether the object is an instance of the specified class or implements an interface.
interface: Java interface keyword is used to implement interface which can only have abstract methods.
long: Java long keyword is used to declare a variable that can hold a 64-bit integer.
new: new keyword is used to create new object.
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: Java protected keyword is an access modifier. It can be accessible within the package and outside the package but through inheritance only. It can't be applied with 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.
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.
synchronized: Java synchronized keyword is used to specify the critical sections or methods in multithreaded code.
this: Java this keyword can be used to refer the current object in a method or constructor.
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.