AP Computer Science

String Methods

100

What method can you use to find the length of a string, and what will it return?

.length() and an integer value with the length

200

String word1 = MoNdaY;

What could you use to make word1 all lowercase?

word1.toLowerCase()

300

If you use the .index("d") method on the word "Friday," what will be returned?

3

400

String word = "AP Computer Science";

System.out.print(word.substring(0, 7));

What is printed?

AP Comp

500

String a = "sleepy";

String b = "awake";

System.out.print(b.compareTo(a));

What is printed?

-18

Wrapper Classes

100

We treat primitive data types as objects by using a...

wrapper class

200

The wrapper classes for int, double, and boolean are...

Integer, Double, and Boolean

300

Java CAN or CANNOT automatically convert between primitive data types and their wrapper class objects?

CAN!

400

Declare a new int using the wrapper class, Integer.

Integer name = new Integer(10)

500

Primitive --> object

Autoboxing or unboxing?

Autoboxing

Ifs, Relational Objects

100

When you do your conditional if statement, is there a semi-colon?

No

200

What are the Java symbols for "and," "or," and "not" used in conditional statements?

&&, ||, !

300

13 % 8 == _____

5

400

Write all the Java equivalents to the symbols below:

1. >

2. <

3. ≥

4. ≤

5. =

6. ≠

1. >

2. <

3. >=

4. <=

5. ==

6. !=

500

Using De Morgan's Law, simplify this expression:

!(A == B && A <= B)

A != B || A > B

Array Lists

100

Can multiple different data types be stored in an array list?

No, an array list needs to be composed of elements of the same data type. 

200

How do you declare an ArrayList?

ArrayList<Datatype> name = new ArrayList<Datatype> (# of elements);

300

Describe what the method add(i, e) does in an ArrayList

It adds element e at index i (it inserts it, does not replace it)

400

In ArrayLists, you cannot store primitive data types (int, double, boolean). So, what do you do if you want to make an ArrayList of ints, doubles, or booleans?

Use their wrapper classes and autobox them.

500

When using selection sort to order ArrayList values from smallest to largest, do you use the < (greater than) or > (less than) symbol?

> Less than

Inheritance

100

The parent class is called the...

Super class

200

What is the keyword that allows us to leverage the constructors and methods in the superclass?

super keyword

300

Fill in the blank (creating a sub class):

public class Parent ____ Child

extends

400

True or False: a sub class has access to everything in the super class regardless of whether it's public or private

False. Must be public

500

Define overriding.

When a method has the same parameter as it's parent class but it performs a different action.