Java Compilation Error: Undefined Class 'Parent'

This code will not compile because the class 'Parent' has not been defined or imported. Therefore, the reference to 'Parent.field_0' is invalid. To fix this error, you need to either define the 'Parent' class in the same file or import it from another file. For example, you could create a separate file named 'Parent.java' containing the 'Parent' class definition, then use an import statement at the top of the current file to make 'Parent' accessible.