The use of strict fields in constructors with control flow introduced the need for the early_larval stackmap frame type to track the state of strict field initialization. An early_larval frame contains a set of NameAndTypes which must be marked as unset but there are no checks to ensure the input values actually refer to a NameAndType.

If an invalid constant pool index or an index that does not refer to a NameAndType is present in an early_larval frame, the vm will crash.

An example from a jcod file:
Attr(#36) { // StackMapTable
              [] { //
                246b, []{#8; #0}, { // CRASH: early_larval_frame with CP index 0 which is invalid
                  21b; // same
                };
                246b, []{#3; #8}, { // early_larval_frame
                  7b; // same_frame
                };
                246b, []{}, { // early_larval_frame
                  9b; // same_frame
                };
              }
            } // end of StackMapTable