public abstract class Shape {

private int x;

private int y;

public abstract void draw();

public void setAnchor(int x, int y) {

this.x = x;

this.y = y;

}

}

Which two classes use the Shape class correctly?

To do multi threading in java we use interfaces and classes defined in java.lang package.

Those classes and interfaces are:

Java.lang.Runnable, Java.lang. Thread, Java.lang.ThreadGroup

Executing two or more blocks (threads) of a program at a time is called MultiThreading.

Executing more than one program simultaniously.(i.e at time)

Ex:

Windows media player  is a program

Internet explorer(IE) is another program executing both the programs  at a time is called multi tasking.

A Thread is a block of code that can be executed in parallel with another block of code.

File[] listFiles();

this method returns list of files stored in a directory.

long lastModified();

we can give this return value to a date object and we can get data to be displayed.

boolean isDirectory();

boolean isFile();