Keywords in Java are reserved words that have a specific meaning and purpose within the Java programming language. These keywords cannot be used as identifiers (names) for variables, classes, methods, or any other programming constructs.

Here's a list of Java keywords with their definitions

abstract - used to declare abstract classes and methods that cannot be instantiated directly.

assert - used to test assumptions during program execution and throw an error if the assumption is false.

boolean - a primitive data type used to represent true or false values.

break - used to exit a loop or switch statement prematurely.

byte - a primitive data type used to represent integer values from -128 to 127.

case - used in switch statements to define different cases for a given variable.

catch - used in exception handling to specify a block of code to be executed when an exception occurs.

char - a primitive data type used to represent a single character in Unicode.

class - used to define a class in Java.

continue - used to skip to the next iteration of a loop.

default - used in switch statements to specify a default case if no other case matches.

do - used to create a do-while loop.

double - a primitive data type used to represent decimal values with higher precision than float.

else - used to specify a block of code to be executed if a conditional statement is false.

enum - used to define enumerated types.

extends - used to indicate that a class is a subclass of another class.

final - used to indicate that a variable, method, or class cannot be changed once it has been initialized.

finally - used in exception handling to specify a block of code to be executed after a try block, regardless of whether an exception is thrown.

float - a primitive data type used to represent decimal values with less precision than double.

for - used to create a for loop.

if - used to specify a block of code to be executed if a conditional statement is true.

implements - used to indicate that a class implements a particular interface.

import - used to import classes and packages from other sources.

instanceof - used to test whether an object is an instance of a particular class.

int - a primitive data type used to represent integer values.

interface - used to define an interface in Java.

long - a primitive data type used to represent integer values with higher range than int.

native - used to indicate that a method is implemented in native code.

new - used to create a new instance of a class.

package - used to define a package in Java.

private - used to specify that a variable or method can only be accessed within the same class.

protected - used to specify that a variable or method can only be accessed within the same class or subclasses.

public - used to specify that a variable or method can be accessed from any class.

return - used to return a value from a method.

short - a primitive data type used to represent integer values from -32768 to 32767.

static - used to indicate that a variable or method belongs to a class rather than an instance of the class.

strictfp - used to indicate that floating-point calculations should adhere to the IEEE 754 standard.

super - used to refer to the parent class of a subclass.

switch - used to create a switch statement that evaluates a single variable and executes a block of code depending on the value of the variable. Each possible value of the variable is defined in a case statement, and a default statement is executed if none of the case statements match the value of the variable. The switch statement can be used with any data type, including int, char, byte, short, enum, and String.

synchronized - used to specify that a method can only be accessed by one thread at a time.

this - used to refer to the current instance of a class.

throw - used to throw an exception.

throws - used to declare that a method may throw a particular type of exception.

transient - used to specify that a variable should not be serialized when an object is written to a file.

try - used to create a block of code that may throw an exception.

void - used to indicate that a method does not return a value.

volatile - used to specify that a variable may be modified by multiple threads.

These keywords have specific meanings within the Java language and cannot be used as variable names or any other identifiers in Java code. It is important to be familiar with these keywords when writing Java programs.