i m a starter into salesforce .. i m getting in this silly code

Here is correct way to your code. You where assigning the age in quotes it will take it as string in palce of integer .For integer value assign  it without quote.

public class Employee1 {
Integer age;
public Employee1()
{
age =50;
}
public integer getAge()
{
return age;
}
public string getName()
{
return'xyz';
}
}