If you've encountered the "document is not defined" error while working with JavaScript, you're not alone. This common error can be frustrating, but it's usually straightforward to resolve once you understand its causes. Let's explore what this error means, why it occurs, and how to fix it.

Over the past two and a half decades, Java has consistently been ranked as one of the top 3 most popular programming languages in the world . As a compiled language, any source code written in Java needs to be translated (i.e., compiled) into machine code before it can be executed.

An IllegalStateException is a runtime exception in Java that is thrown to indicate that a method has been invoked at an illegal or inappropriate time. To use an analogy, invoking a method in Java when the system is not in the appropriate state is like trying to start a car while it is in "Drive". Just as the car will not start because it is unsafe, a method call results in an IllegalStateException when the internal conditions necessary for its execution are not met.