Tuners Past And Present

A typical example of a compile-time exception is missing parentheses. The compiler or will prompt the developer that the parenthesis are missing and should be inserted. The code will never compile unless parentheses are inserted. In contrast runtime exceptions are critical and cannot be caught at compile time. If they are not handled they can crash the program at runtime. For example if a number is divided by zero at runtime a will be thrown at runtime. This exception is not caught at runtime because the compiler does not know in advance that the number will be divided by zero.

Another extremely important runtime exception that you need to understand thoroughly for proper planning and error handling is the null pointer exception. To learn more about exceptions take the course on . What is a null pointer exception? Popular Courses In object-oriented programming Phone Number List when a class is instantiated its objects are stored in computer memory. To reference the object and use it in a program you need a reference variable of the class type that has the object that must be instantiated. This reference variable actually points to a memory address of the object. To call the object's methods and access the properties and fields of the class use this reference variable.



A null pointer exception occurs when an object's reference variable contains a null value and the object is used to call a method or instance variable.  exception occur? For ease of explanation we explain the NullPointerException with the help of code and code two of the most widespread object-oriented languages. Null pointer exceptions also occur in and where an actual pointer is used to point to a memory location. The following example demonstrates how a null pointer exception in and actually occurs. Code Suppose there is a class called . The class is defined as follows public class Person public integer Age public string name public return age public voidage the age.