I just gave you an example from the top of my head. Here is another more realistic one, which occurred to me during the time I wrote a toy JVM: a Java class file contains a constant pool with different kinds of types. During the loading process this pool can be references by other entities as well, but they require the necessary type. Assuming verified byte code, this will be the case, but if we care about verification as well then you will quickly get into the situation where you simply can’t handle “during the loading of this class’s nth method, one of the constant pool references were of incorrect type”. It can’t be handled at method loading (or even more nested), and panicking is not the correct behavior (you only don’t want to load the given class). So you have to manually bubble it up for no benefit.