Java basic syntax
- 1. Java object has a State and Behavior
- 2. State (Variables) Variable or Field is nothing but the property of the class class “computer” may have property like : – Model – mem_size – hd_size – os_type etc
- 3. Class Name first letter should be in Upper Case If several words are used to form a name of the class each inner words first letter should be in Upper Case. Ex: MyFirstJavaExample
- 4. Behavior (Methods) Method is nothing but the operation that an object can perform It tells How an object can interact with outside world
- 5. Method Name All method names should start with a Lower Case letter. Ex: public void myMethodName( )
- 6. Java Application is a Java class having main method
- 7. main method should be public – Class loader need to access this method should be static – method would be executed without an object
- 9. ● Compile the code – javac HelloWorld.java ● Run the code – java HelloWorld
- 10. Java is Case Sensitive ● Both the compiler (javac) and launcher (java) are case- sensitive. ● Type all code, commands, and file names exactly as shown. – HelloWorld is not the same as helloworld
- 11. Program File Name Name of the program file should exactly match the class name. When saving the file you should save it using the class name and append ‘.java’ to the end of the name. Example : class ‘HelloWorld’ should be saved in file ‘HelloWorld.java’
- 12. Java Identifiers All java components require names. Names used for classes, variables and methods are called identifiers.
- 13. Java Keywords These are reserved words and may not be used as constant or variable or any other identifier names. Examples: abstract, boolean, break, byte, class, package etc.
- 14. Comments in Java Java supports single line and multi-line comments very similar to c and c++. All characters available inside any comment are ignored by Java compiler.
- 15. Using Blank Lines A line containing only whitespace is known as a blank line, and Java ignores it.