Introduction to Java

1
Introduction to Java Part 6

• Informatik III

2
Collections
3
Collections

• The package java.util contains a family of
  collection classes.
• Here we will only mention one
• ArrayList
• Lists, e.g. ArrayLists can hold an unlimited
  number of objects
• You can use method add(object) to add an object
  to an ArrayList

4
Collections

• To define a ArrayList
• ArrayListltTypgt var new ArrrayListltTypgt
• The Typ is the type of objects this array should
  store, for example if the array should store
  objects of type Person
• ArrayListltPersongt var new ArrrayListltPersongt
• Easy for each loop available (see next slide)
• Use method add(o) to add to the ArrayList
• Use get(index) to get the index element (starts
  with 0)

5
Collections

6
Exercise

• Lets develop based on the hand-outs