Why am i getting 'nullpointerexception' in java?

The `NullPointerException` is thrown when the JVM attempts to access an object or call a method on an object which is currently `null`. It's one of the most common issues faced by Java developers. Example:

String str = null;
int length = str.length();
Solution:

String str = null;
if(str != null) {
    int length = str.length();
}
Always make sure to check for null values before accessing object's methods or properties.

Beginner's Guide to Java