Java basic-syntax
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A Java class has both state and behavior. The state is defined by variables called fields, while the behavior is defined by methods that describe what operations an object can perform. Class names, variable names, and method names all have specific naming conventions in Java such as starting with a capital letter or lowercase letter. A Java application requires a class with a main method that is public, static, and matches the file name for the program to run properly.
Java basic-syntax
- 1. Java Class Java class 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 Names 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 Names All method names should start with a Lower Case letter. Ex: public void myMethodName( )
- 6. Java Application Java classes having main method
- 7. main method should be public – because Class loader need to access this method should be static – because method would be executed without an object
- 9. Compile the source file
- 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 : Assume ‘HelloWorld’ is the class name. Then the file should be saved as ‘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.