array list

Question 1

generics

Answer 1

effectively build a template than can be instantiated in many ways (form of polymorphism)

Question 2

declare an array list

Answer 2

ArrayList arrName;

Question 3

create a new ArrayList object and store the reference.

Answer 3

arrName = new ArrayList();

Question 4

how to add objects to an array list

Answer 4

arrName.add(1.1F); 
or
Float f = new Float(3.14F); arrName.add(f);
or specify position 
arrName.add(2.3F);

Question 5

how to remove items from array list

Answer 5

arrName.remove(three);
use reference to the object in list (returns Boolean (if that item was in the list or not))
or
arrName.remove(1);
specify its 0-based index position number in list ( returns a reference to removed object)

Question 6

contains method

Answer 6

(arrName.contains(seek));

returns a Boolean value indicating whether that object is in the list.

Question 7

get method

Answer 7

returns a reference to the object at the 0-based index position
Student ref = myStudents.get(3); ref.setUID(987654321);

Question 8

to find the current length of an array

Answer 8

int length = arrName.size();

Question 9

iterate through array list

Answer 9

int length = arrName.size(); for (int i=0; I

Question 10

shallow copy array list code

Answer 10

ArrayList newArr; newArr = new ArrayList(oldArr);

Question 11

for each loop

also allows us to iterate through array lists

Answer 11

for (Typename iteratedVal : collection) { //process the iteratedVal object
}

NOTE: You cannot alter the structure of a list while iterating through it using a for-each style loop!!!

Question 12

deep copy array list code

Answer 12

ArrayList dupList;
dupList = new ArrayList();
for (StringBuffer str : origList) {
dupList.add(new StringBuffer(str));
}