Keywords in Java

We have already learnt about the keywords defination , different keywords and some important points about it in the previous post about Keywords and Identifiers in Java.

Now , after seeing all that keywords you must be feeling What do they do ? or What are their functions. In this post , we have put all the functions of all the 50 keywords in a tabular format.

Table of Keywords and their descriptions :-                                   (-Each type is arranged alphabetically-)
Class ,Method and Variables modifiers	1.        abstract	Used to declare a class or method to be abstract. It signifies something empty. It is used to declare a class or method without any implementation. Object of a abstract class cannot be instantiated ,but can be extended by other classes.
	2.        class	Used to define a class. We have discussed class in detail. Click here.
	3.        enum	Used to declare an enumerated type.
	4.        extends	Used in sub-class declaration to specify the super class/parent class to the sub-class.
	5.        final	Used to define an entity that cannot be changed or extended later.
	6.        implements	Used in class declaration to specify one or more interfaces that are implemented by the current class.
	7.        interface	Used to declare a special type of class that only contains abstract methods, constant fields which are static or final and static interfaces.
	8.        native	Used to show that the implementation is not done in the same source file and ,also , it is in different language.
	9.        new	Used for object creation and providing memory to it , generally , on heap.
	10.     static	Used to declare a method, field or inner class as class members rather object members.
	11.     strictfp	Used to ensure portability by restricting the precision and rounding of floating points in Java.
	12.     synchronized	Used to ensure that at a time only one thread can be accessed by a method by using mutex lock.
	13.     transient	Used to prevent fields from being serialized. Transient fields are always skipped when objects are serialized.
	14.     volatile	Indicates that a variable may be modified by concurrently running threads. It can also be called as a lock-free mechanism.
Flow Control	15.     break	Used to exit the current enclosing block or skip the immediate statement. Actually , it transfers the flow of program to the other part of program.
	16.     case	Used within switch statements. It executes a block of code depending on the switch expression .
	17.     continue	Used to resume program execution at the end of the current loop body.
	18.     default	Used within the switch statement. Executes a block of code , if none of the value of case keywords is matching with the switch statement value.
	19.     do	Executes a block of code one time and then based on the while statement determines will that block of code be executed again.
	20.     else	Executes a block of code when the if condition is not true.
	21.     for	Used to define a loop that reiterates statements. The for loop specifies the statements to be executed , exit condition , updating operations and  initialization variables for the loop. *A new concept of "enhanced for loop" has been specified where each iteration of the loop executes block of code using a different element in the array or Iterable.
	22.     if	Used to a conditional test and executes a block of code if the test evaluates to true . If it evaluates to false , an optional block of code is defined with the else keyword .
	23.     instanceof	Used to check an object belongs to which class. The instanceof evaluates to true if an object belongs to a specified class or its super class; else raises compilation error.
	24.     return	Used to finish the execution of method. It can be followed by a value to pass to the caller method.
	25.     switch	Used to evaluate a variable that can later be matched with a value specified by the case keyword in order to execute a block of statements.
	26.     while	Used to execute a block of code in loop if given logical boolean  expression evaluates to true.
Special Reference Keywords	27.     super	Reference variable referring to immediate super class / parent class.
	28.     this	Reference variable referring to the instance of current object.
Access Modifiers	29.     private	Used to make method or variable accessible only within its own class.
	30.     protected	Used to make method or variable accessible only  to classes in same package or to subclasses(derived class) of the class.
	31.     public	Used to make method or variable accessible to everybody.
Primitives	32.     boolean	Used with variable that can have value as true or false only.
	33.     byte	An 8-bit signed integer.
	34.     char	An Unicode character(16-bit unsigned integer).
	35.     double	An 64-bit signed floating-point number.
	36.     float	An 32-bit signed floating-point number.
	37.     int	An 32-bit signed integer.
	38.     long	An 64-bit signed integer.
	39.     short	A 16-bit integer value
Error Handling	40.     assert	Evaluates a conditional expression to verify the programmer’s assumption. If the condition is not true, an AssertionError is thrown. Generally used for debugging purpose.
	41.     catch	Declares a block of code that executes if exception occurs .
	42.     finally	Block of code that follows try block code and executes no matter how exception is handled.
	43.     throw	Used to pass an exception to method that called this method
	44.     throws	Used to specify which exceptions are not handled in the method and will be passed on to the next higher level of the program.
	45.     try	Used with the block of code that will be tried for execution, but which may cause an exception.
Package Control	46.     import	Used at the beginning of a source file to declare what packages or classes are to imported.
	47.     package	Used to keep classes together which have a relation between them.
Void keyword	48.     void	Used to indicate that the method does not have a return type.
Keywords unused	49.     const	Not used. 'final' keyword can be used in place of this keyword.
	50.     goto	Not used.

So we have learnt the functions of all the 50 keywords present in Java programming langauge.

Don't worry , if you did not understand the meaning of all the above stuff. We will be learning the working of all of them as and when they come in further programs.

KEEP COMPILING !!