Basic java Syntax
| About java programs,it is very important to keep in mind the following points. |
|---|
- Case Sensitivity: Java is case sensitive, which means identifier Hello and hello would have different meaning in Java.
- Class Names:For all class names the first letter should be in Upper Case.
- if several words are used to form a name of the class,each inner word's first letter should be Upper Case.
- Example class MyFirstJavaClass.
- Method Names: All Method names should start with a Lower Case letter.
- If several words are used to form the name of the method,then each inner word's first letter should be in Upper Case.
- Example public void myMethodName()
- Program File Name: Name of the program file should exactly match the class name.
- when saving the file,you should save it the class name(Remember Java is case sensitive and append.'.Java' to the end of the name(if the file name and the class name do not match your program will not complie)
- Example:Assume 'MyFirstJavaProgram'is the class name.Then the file should be saved as MyFirstJavaProgram.java
- public static void main(Stringargs[]) : Java program processing starts from the main() method which is mandatory part of every Java program.
Hello World Example
class HelloWorld
{
public static void main(String args[])
{
System.out.println("Hello world");
}
}
If all goes well you see the following output.
Hello world
Explanation:
- All code is contained within a class,in this case HelloWorld.
- class keyword is used to declare a class in java.
- public keyword is an access modifier which represents visibility,means visible to all.
- The file name must match the class name and have a .java extension, for example: HelloWorld.java.
- All executable statements are contained within a method,in this case named main();
- Use System.out.println() to print text to the terminal.
