question: public boolean isBeginningInstruction ( ) { if ( predecessors . size ( ) == 0 ) { return false ; } return predecessors . first ( ) . instructionIndex == - 1 ; }
target:  Is this instruction a "beginning instruction". A beginning instruction is defined to be an instruction that can be the first successfully executed instruction in the method. The first instruction is always a beginning instruction. If the first instruction can throw an exception, and is covered by a try block, then the first instruction of any exception handler for that try block is also a beginning instruction. And likewise, if any of those instructions can throw an exception and are covered by try blocks, the first instruction of the corresponding exception handler is a beginning instruction, etc. <p/> To determine this, we simply check if the first predecessor is the fake "StartOfMethod" instruction, which has an instruction index of -1.