void waitForSignal() {

Object obj = new Object();

synchronized (Thread.currentThread()) {

obj.wait();

obj.notify();

}

}

Which statement is true?

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();