Rectangle Class Include Try-catch And Exception Handling

The requirement is to write a rectangle class and a test class, which include try-catch blocks and exception handling. Exceptions, involving try, catch, throw, throws, and finally commands,how to write a code about basic things, but in the test class, it gives me specific width and height so that i dont konw how to write a try-catch blocks an exception handling in this test class.There is my two classes, they are separated.

public class Rectangle {
double width ;
double height ;
Rectangle(){
width = 1;
height = 1;

[code]....