Java has more than 50 keywords for the different operations. Here is the list of all the keywords and its purpose.
Keyword | Description |
---|---|
abstract | Abstract keyword can be use with classes and methods to defer the actual implementation to the child classes. |
assert | This keyword used for testing the truth of a condition. |
boolean | Indicates that a value is either true or false. |
break | Jumps out of a loop or switch block. |
byte | Indicates that a value is an 8-bit whole number. |
case | This is used in the switch block to define the different conditions using the case block. |
catch | This is used with the exception handling. To catch the exception thrown from the above code will be handled. |
char | Indicates that a value is a character (a single letter, digit, punctuation symbol, and so on) stored in 16 bits of memory. |
class | Used for declaring a class. A structure of an object for storing data and state. |
const | You can’t use this word in a Java program. The word has no meaning. Because it’s a keyword, you can’t create a const variable. |
continue | Forces the abrupt end of the current loop iteration and begins another iteration. |
default | Introduces a path of execution to take when no case is a match in a switchstatement. |
do | Causes the computer to repeat some statements over and over again (for instance, as long as the computer keeps getting unacceptable results). |
double | Indicates that a value is a 64-bit number with one or more digits after the decimal point. |
else | Introduces statements that are executed when the condition in an if statement isn’t true. |
enum | Creates a newly defined type — a group of values that a variable can have. |
extends | Creates a subclass — a class that reuses functionality from a previously defined class. |
final | Indicates that a variable’s value cannot be changed, that a class’s functionality cannot be extended, or that a method cannot be overridden. |
finally | Introduces the last will and testament of the statements in a try clause. |
float | Indicates that a value is a 32-bit number with one or more digits after the decimal point. |
for | Gets the computer to repeat some statements over and over again (for instance, a certain number of times). |
goto | You can’t use this word in a Java program. The word has no meaning. Because it’s a keyword, you can’t create a goto variable. |
if | Simple condition to enter a block. |
implements | Reuses the functionality from a previously defined interface. |
import | Enables the programmer to abbreviate the names of classes defined in a package. |
instanceof | Tests to see whether a certain object comes from a certain class. |
int | Indicates that a value is a 32-bit whole number. |
interface | Introduces an interface, which is like a class, but less specific. (Interfaces are used in place of the confusing multiple-inheritance feature that’s in C++.) |
long | Indicates that a value is a 64-bit whole number. |
native | Enables the programmer to use code that was written in another language (one of those awful languages other than Java). |
new | Creates an object from an existing class. |
package | Puts the code into a package — a collection of logically related definitions. |
private | Indicates that a variable or method can be used only within a certain class. |
protected | Indicates that a variable or method can be used in subclasses from another package. |
public | Indicates that a variable, class, or method can be used by any other Java code. |
return | Ends execution of a method and possibly returns a value to the calling code. |
short | Indicates that a value is a 16-bit whole number. |
static | It implies that the variable or method is bound to the class and not to the instance of that class. |
strictfp | Limits the computer’s ability to represent extra large or extra small numbers when the computer does intermediate calculations on float and double values. |
super | Refers to the superclass of the code in which the word super appears. |
switch | Tells the computer to follow one of many possible paths of execution (one of many possible cases), depending on the value of an expression. |
synchronized | To lock a particular piece of code or method while one thread is executing. |
this | A self-reference — refers to the object in which the word this appears. |
throw | Creates a new exception object and indicates that an exceptional situation (usually something unwanted) has occurred. |
throws | Indicates that a method or constructor may pass the buck when an exception is thrown. |
transient | Indicates that, if and when an object is serialized, a variable’s value doesn’t need to be stored. |
try | Introduces statements that are watched (during runtime) for things that can go wrong. |
void | Indicates that a method doesn’t return a value. |
volatile | Imposes strict rules on the use of a variable by more than one thread at a time. |
while | It is a loop to iterate the list of values till it satisfy a condition. |