Java syntax
part 8/46 · 86.7 KB total
──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
Program structure
Java applications consist of collections of classes. Classes exist in packages but can also be nested inside other classes.
main method
Every Java application must have an entry point. This is true of both graphical interface applications and console applications. The entry point is the main method. There can be more than one class with a main method, but the main class is always defined externally (for example, in a manifest file). The main method along with the main class must be declared public. The method must be static and is passed command-line arguments as an array of strings. Unlike C++ or C#, it never returns a value and must return void.
public static void main(String[] args) {
}
Packages
Packages are a part of a class name and they are used to group and/or distinguish named entities from other ones. Another purpose of packages is to govern code access together with access modifiers. For example, java.io.InputStream is a fully qualified class name for the class InputStream which is located in the package java.io.
A package is declared at the start of the file with the package declaration:
package myapplication.mylibrary;
public class MyClass {
}
──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────