question: private void ensureCapacityHelper ( int minCapacity ) { int oldCapacity = elementData . length ; if ( minCapacity > oldCapacity ) { Object [ ] oldData = elementData ; int newCapacity = ( capacityIncrement > 0 ) ? ( oldCapacity + capacityIncrement ) : ( oldCapacity * 2 ) ; if ( newCapacity < minCapacity ) { newCapacity = minCapacity ; } elementData = new Object [ newCapacity ] ; System . arraycopy ( oldData , 0 , elementData , 0 , elementCount ) ; } }
target:  This implements the unsynchronized semantics of ensureCapacity. Synchronized methods in this class can internally call this method for ensuring capacity without incurring the cost of an extra synchronization.