It is very important to know about the Java keywords before you go to develop Java program. These keywords are part and parcel of Java program. In this article I will introduce you with some Java keywords. There are almost 50 keywords in java. Some of them are explained below:
Class: It is used to define an implementation of a particular kind of object. A class can have class fields, methods and inner classes.
Import: This keyword is used at the beginning of a source file( before class ) to import classes or even entire java packages.
Public: It is used to declare methods and fields public.
Static: It is used to declare a field, method or inner class as a class field.
Void: It is used to declare a method that does not return any value.
Double: It is used to declare a double field. A double is primitive data type that is capable of storing decimal number.
Int: Int is a primitive data type that is capable of storing a 32-bit whole number.
If: It is used to create an if statement. The if statement test a boolean expression.
Case: This keyword is used to create individual individual cases in a switch statement.
Switch: The switch keyword is used in conjunction with the case and default keywords. It evaluates a variable and matches it to a specific case.
Else: It is used in conjunction with the if keyword to create an if-else statement.
While: It is used to create a while and do-while loop, which tests a boolean expression and keeps running the same block of code until the boolean expression returns false.
Private: It is used to declare methods and fields private.
Boolean: A boolean is a primitive data type that can store only two values: true or false.
Break: Break is used to immediately breakout of the loop or switch statement it is inside of.
Abstract: It is used to declare a class or method abstract.
Assert: This keyword was added in J2SE 1.4 and is used primarily in the debugging phase of programming.
Byte: This keyword is a primitive data type that is capable of storing 8-bit whole number.
Float: It is a primitive data type that is capable of storing a 32-bit floating point number ie, decimal number.
For: It is used to create a for loop. There are three parts of a for loop- initialization, boolean expression and incrementation.
Throw: It is used to throw an expression.This causes execution to continue with the first enclosing exception handler by the catch keyword.
Catch: It is used with the try keyword to handle an exceptions thrown within the try block.
Try: Try keyword is used in conjunction with the catch keyword to handle exceptions. I f an exception is thrown inside the try block, a catch block can handle the exceptions within the method.
Long: It is used to declare a long field. Long is a primitive data type that is capable of storing a 64-bit whole number.
Final: This keyword is used to to define an entity once and only once.
Do: It is used in conjunction with the while keyword to create a do-while loop.
New: New keyword is used to create a new instance of an array or object.
Default: This default keyword is used in a switch statement. The block of statements in the default case is executed if the value doesn't match any other case.
Continue: It is used in a loop to resume program execution.
I have introduced a very few Java keywords here, but I will try to show you how these keywords work with examples and video tutorials in upcoming Java programming article. Until then keep eyes on this blog.
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