What is the difference between java compile time inheritance and run time inheritance?

The term "inheritance" refers to a situation in which attributes and/or behaviors are passed on from one object to another. When this occurs at compile-time, it is usually called "subclassing" since one class, the child, is lower than the parent in the inheritance hierarchy. The Java programming language reserves the keyword "extends" for compile-time inheritance.

Runtime inheritance refers to the ability to construct the parent/child hierarchy tree at runtime. While Java does not allow this natively, there are a number of projects and technologies available that will enable you to modify the bytecode of a class after compilation. While they really aren't intended to use for runtime inheritance, they could do the job.