6.1. Assumptions: The Meaning of “Must”

The description of each instruction is always given in the context of Java Virtual Machine code that satisfies the static and structural constraints of §4. In the description of individual Java Virtual Machine instructions, we frequently state that some situation “must” or “must not” be the case: “The value2 must be of type int.” The constraints of §4 guarantee that all such expectations will in fact be met. If some constraint (a “must” or “must not”) in an instruction description is not satisfied at run time, the behavior of the Java Virtual Machine is undefined.

The Java Virtual Machine checks that Java Virtual Machine code satisfies the static and structural constraints at link time using a class file ...

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