Java Performance in collections -01

USE APPROPRIATE COLLECTION

Array List Vs Linked List

ArrayList al = new ArrayList();

For(int i=0;i

{

          al.get(i);

}                                                                           Takes 281 ms

                            

LinkedList ll = new LinkedList();

For(int i=0;i

{

          ll.get(i);

}                                                                            Takes 5828 ms

Sequential access

ArrayList al = new ArrayList();

For(Iterator I = al,iterator();I,hasNext();)

{

          i.next();

}                                                                                     Takes 1375 ms

LinkedList ll = new LinkedList ();

For(Iterator I = ll,iterator();I,hasNext();)

{

          i.next();

}                                                                                     Takes 1047 ms

Note:- ArrayList is good for random access

          LinkedList is good for sequential access

Better in the best of both

ArrayList al = new ArrayList();

For(int I =0;i

{

          al.get(i);

}                                                                                     Takes 281 ms

LinkedList ll = new LinkedList ();

For(Iterator I = ll,iterator();I,hasNext();)

{

          i.next();

}                                                                                     Takes 1047 ms

Note:- Random access is better than sequential access

Insertion in ArrayList Vs LinkedList

ArrayList al = new ArrayList();

For(int I =0;i

{

          al.add(0, Integer.valueOf(i));

}                                                                                     Takes 328 ms

LinkedList ll = new LinkedList ();

For(int I =0;i

{

          ll.add(0, Integer.valueOf(i));

 }                                                                                    Takes 109 ms

Note:- LinkedList does insertion better than ArrayList

Vector vs. ArrayList

Vector is like to ArrayList but it is Synchronized version

Accession and Insertion in Vector Vs ArrayList

Random access

ArrayList al = new ArrayList();

For(int I =0;i

{

          al.get(i);

}                                                                                     Takes 281 ms

Vector vt = new Vector();

For(int I =0;i

{

          vt.get(i);

}                                                                                  Takes 422 ms

Sequential access

ArrayList al = new ArrayList();

For(Iterator I = al,iterator();I,hasNext();)

{

          i.next();

}                                                                                     Takes 1375 ms

Vector vt = new Vector();

For(Iterator i= vt,iterator();I,hasNext();)

{

          I,next();

}                                                                                     Takes 1890 ms

Insertion

ArrayList al = new ArrayList();

For(int I =0;i

{

          al.add(0, Integer.valueOf(i));

}                                                                                     Takes 328 ms

Vector vt = new Vector ();

For(int I =0;i

{

          vt.add(0, Integer.valueOf(i));

}                                                                                                          Takes 360 ms

Vector is slower than Array List in every method. Use Vector if only synchronize needed

Summary: java.util.List