Is it possible in Java to create or modify the implementation of a method in a static class?

In Java, it is not possible to change the implementation of a method in a static class after it has been compiled, because static methods are associated with the class, not with an instance, and do not support polymorphism. Also, Java does not support changing code at runtime. However, design patterns such as delegation can be used to change behavior, or bytecode injection tools can be applied, but these are complex and non-standard approaches.