Structure of Java Program

Structure of Java Program

Structure of a java program is the standard format released by Language developer to the Industry programmer.

Sun Micro System has prescribed the following structure for the java programmers for developing java application.

• A package is a collection of classes, interfaces and sub-packages. A sub package contains collection of classes, interfaces and sub-sub packages etc. java.lang.*; package is imported by default and this package is known as default package.
• Class is keyword used for developing user defined data type and every java program must start with a concept of class.
• "ClassName" represent a java valid variable name treated as a name of the class each and every class name in java is treated as user-defined data type.
• Data member represents either instance or static they will be selected based on the name of the class.
• User-defined methods represents either instance or static they are meant for performing the operations either once or each and every time.
• Each and every java program starts execution from the main() method. And hence main() method is known as program driver.
• Since main() method of java is not returning any value and hence its return type must be void.
• Since main() method of java executes only once throughout the java program execution and hence its nature must be static.
• Since main() method must be accessed by every java programmer and hence whose access specifier must be public.
• Each and every main() method of java must take array of objects of String.
• Block of statements represents set of executable statements which are in term calling user-defined methods are containing business-logic.
• The file naming conversion in the java programming is that which-ever class is containing main() method, that class name must be given as a file name with an extension .java.