Null Pointer Exception in Java
A Null Pointer Exception in java is a type of runtime exception thrown when a Java program tries to use an object reference that contains a null value. A null pointer exception can be thrown in the following scenarios:
- Calling an instance method of a null object.
- Accessing or modifying a field of a null object.
- Gets the length of null as if it were an array.
- Access or modify null slots as if they were arrays.
- Throw null as if it were a Throwable value.
Null Pointer Exception in Java Example
Here is an example of a Null Pointer Exception thrown when the length() method of a null String object is called.
In this example, the printLength() method calls the String’s length() method without performing a null check before calling the method. Since the string value passed from the main() method is null, running the above code will result in a Null Pointer Exception.