public void copyFrom(Path other){
  grow(other.length - 1);
  System.arraycopy(other.blockIdList,0,this.blockIdList,0,other.length);
  this.length=other.length;
  this.cachedHashCode=other.cachedHashCode;
}

public void copyFrom ( Path other ) { grow ( other . length - 1 ) ; System . arraycopy ( other . blockIdList , 0 , this . blockIdList , 0 , other . length ) ; this . length = other . length ; this . cachedHashCode = other . cachedHashCode ; }
make this path identical to the given one .
