java best practices

A NullPointerException is a runtime exception in Java that happens when you attempt to perform an operation on a null object reference. In other words, you're attempting to access a member (such as a method or field) of an object that hasn't yet been initialized, which results in a null reference.

The String Buffer class in Java provides a modifiable sequence of characters. It is commonly used when you need to dynamically edit strings without continuously generating new objects.