Java syntax
part 9/46 · 86.7 KB total
──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
Classes with the public modifier must be placed in the files with the same name and java extension and put into nested folders corresponding to the package name. The above class myapplication.mylibrary.MyClass will have the following path: myapplication/mylibrary/MyClass.java.
Import declaration
Type import declaration
A type import declaration allows a named type to be referred to by a simple name rather than the full name that includes the package. Import declarations can be single type import declarations or import-on-demand declarations. Import declarations must be placed at the top of a code file after the package declaration.
package myPackage;
import java.util.Random; // Single type declaration
public class ImportsTest {
public static void main(String[] args) {
/* The following line is equivalent to
* java.util.Random random = new java.util.Random();
* It would have been incorrect without the import.
*/
Random random = new Random();
}
}
Import-on-demand declarations are mentioned in the code. A "type import" imports all the types of the package. A "static import" imports members of the package.
import java.util.*; /*This form of importing classes makes all classes
in package java.util available by name, could be used instead of the
import declaration in the previous example. */
import java.*; /*This statement is legal, but does nothing, since there
are no classes directly in package java. All of them are in packages
within package java. This does not import all available classes.*/
Static import declaration