What is NullPointerException in Java with example?

What is NullPointerException in Java with example?

NullPointerException is a runtime exception and it is thrown when the application try to use an object reference which has a null value. For example, using a method on a null reference.

What is a NullPointerException in Java?

NullPointerException is a runtime exception in Java that occurs when a variable is accessed which is not pointing to any object and refers to nothing or null. Since the NullPointerException is a runtime exception, it doesn’t need to be caught and handled explicitly in application code.

How do you deal with NullPointerException in Java?

In Java, the java. lang. NullPointerException is thrown when a reference variable is accessed (or de-referenced) and is not pointing to any object. This error can be resolved by using a try-catch block or an if-else condition to check if a reference variable is null before dereferencing it.

In which case the NullPointerException will be thrown?

A null pointer exception is thrown when an application attempts to use null in a case where an object is required. These include: Calling the instance method of a null object. Accessing or modifying the field of a null object.

Is FileNotFoundException a runtime exception?

I know FileNotFound is Checked Exception but though it is, only during the Run time this exception will occur.It is more like Arithmetic Exception(Unchecked). Whether it is checked or unchecked the exception will happen only during runtime.

Is ArrayIndexOutOfBounds a runtime exception?

The ArrayIndexOutOfBounds exception is a run-time exception. Java’s compiler does not check for this error during compilation.

Is NullPointerException throwable?

Class NullPointerException Thrown when an application attempts to use null in a case where an object is required. These include: Accessing or modifying the slots of null as if it were an array. Throwing null as if it were a Throwable value.

How do I capture a null pointer exception?

To avoid the NullPointerException, we must ensure that all the objects are initialized properly, before you use them. When we declare a reference variable, we must verify that object is not null, before we request a method or a field from the objects.

Can we throw NullPointerException Java?

In Java, a special null value can be assigned to an object reference. NullPointerException is thrown when program attempts to use an object reference that has the null value. These can be: Throwing null, as if it were a Throwable value.

Why is IOException checked exception?

Because IOException is a checked exception type, thrown instances of this exception must be handled in the method where they are thrown or be declared to be handled further up the method-call stack by appending a throws clause to each affected method’s header.

Why do I get a NullPointerException?

Calling the instance method of a null object.

Accessing or modifying the field or a null object.

Taking the length of the null as if it were an array.

Accessing or modifying the slots of null as if it were an array.

Throwing null as if it were a Throwable value.

What is a null pointer exception in Java?

Null Pointer Exception In Java. Null is a special kind of value and is mainly used to indicate that no value is assigned to a reference variable. One application is the Singleton pattern which ensures that only one instance of a class is created and also, aims for providing a global point of access to the object.

What is Java nullpoint exception?

Null Pointer Exception. Java is an object-oriented programming language.

Causes Of Null Pointer Exception. Null pointer exception can occur in different ways with different causes.

Solutions For Null Pointer Exception.

When does a null pointer exception occur?

The Null Pointer Exception became famous because its error description never gave an idea about a null variable in the code, due to which the exception actually occurred. The error report mentions only the line number where the issue is found.