¿Qué es el error Java Lang NullPointerException?

What is Java Lang NullPointerException error?

NullPointerException is an error in Java that occurs as a Java program attempts to use a null when an object is required. The NullPointerException is a public class that extends the RuntimeException. Similarly, if an object is null and you try to access or modify the field of that null object, this error will occur.

Yes, it will catch ApplicationException as it derives from Exception . Handling the base exception should be fine in most cases unless you need to log or do something with a different type of exception…

NullPointerException is thrown when program attempts to use an object reference that has the null value. Accessing or modifying the slots of null object, as if it were an array. Throwing null, as if it were a Throwable value. When you try to synchronize over a null object.

1. Why NullPointerException occur in the code NullPointerException is a situation in code where you try to access/ modify an object which has not been initialized yet. It essentially means that object reference variable is not pointing anywhere and refers to nothing or ‘ null ‘. A example java program which throws null pointer exception. 2.

NullPointerException is thrown when program attempts to use an object reference that has the null value. These can be: Invoking a method from a null object. Accessing or modifying a null object’s field. Taking the length of null, as if it were an array. Accessing or modifying the slots of null object, as if it were an array.

you are trying to iterate over null. Check the constructor to ensure the relatedList is initialized. Consider adding an assertion before the for loop to ensure the value is valid. If the Error line isn’t the For loop then it might be the rList.objectName being null and then calling .toLowerCase () on it.

// IllegalArgumentException if s is null. The ternary operator can be used to avoid NullPointerException. First, the Boolean expression is evaluated. If the expression is true then, the value1 is returned, otherwise, the value2 is returned. We can use the ternary operator for handling null pointers: