question: private void ensureFDCapacity ( int idx ) { if ( idx >= failureDetectionPorts . length ) { int [ ] p = new int [ idx + 10 ] ; if ( failureDetectionPorts . length > 0 ) { System . arraycopy ( failureDetectionPorts , 0 , p , 0 , failureDetectionPorts . length ) ; } Arrays . fill ( p , idx , idx + 9 , - 1 ) ; failureDetectionPorts = p ; } }
target:  ensures that there is a slot at idx to store an int