CS Midterm

In order to run a static method, you must run it for a particular object (the current object)

False

In order to run an instance method, you must run it for a particular object (the current object)

True

An instance variable can be declared as "static"

False

The same class can contain some members that are static and some members that are non-static.

True

Which kinds of variables are given default values if you do not initialize them? (Local/ instance/static? Which ones?)

instance and static

Default value for all primitive types?

0

Default value for boolean statements

False

Default value for char

ASCII code for 0

Default value for reference variables

null

When writing JUnit tests, is it better to write many small tests, or a few long ones?

Many small ones

If a JUnit test has several separate ASSERTIONS in it, will the test continue after one of the assertions fails?

No

If a JUnit test suite has several different JUnit tests in it (separate methods), will the rest of the tests run after one of them fails?

Yes

In what kind of methods does it make sense to use "this"?

Instance methods and constructors

What does "this" refer to?

The "current object"

If you do not write any constructors, what values will instance variables that are REFERENCES be assigned?

null

Under what circumstances will Java provide a default constructor for you automatically?

If I don't write a constructor

What do term do you use when you insert an element onto a stack?

push

What do term do you use when you remove an element from a stack?

pop

When you push an entry into the stack does it go on the top or bottom?

top

When you pop an entry from the stack, does it come off the top or bottom?

top

In java, when you pass a reference variable as an argument to a method, it is possible for the method to modify the object to which the variable refers.

Yes

What does API stand for?

Application Programming Interface

What type of members would you look for when identifying members that are a part of the API for the class?

"public" members

If a member is declared as public, can it be accessed from inside the SAME class?

Yes

If a member is declared as public, can it be accessed from ANOTHER class?

Yes

If a member is declared as private, can it be accessed from inside the same class?

Yes

If a member is declared as private, can it be accessed from another class?

No

What is a "setter"?

A method that initializes an instance variable

What is a "getter"?

A method that returns the value of an instance variable

If you change a class in such a way that the API changes, then other classes which depend on this one will have to be re-coded.

True

If you change a class WITHOUT modifying the API, then other classes which depend on this one will have to be re-coded.

False

What package is the Scanner class located in?

java.util

What is full name of the Scanner class?

java.util.Scanner

What is accomplished when you type "import java.awt.Color;" at the top of a file?

The IDE will know you're talking about the Color class in the package called java.awt

Which java package is automatically imported in its entirety into every Java program you write?

java.lang

What method of the String class can be used to pick out one particular character in the string?

charAt

What method of the String class can tell you how many characters are in the String?

.length()

What is accomplished when you type "import java.awt.*;" at the top of a file?

You import EVERYTHING that is in the package java.awt.

What method of the String class can be used to compare to Strings for alphabetical order?

.compareTo()

What method of the String class can select a portion of an existing String?

substring

Describe how a continue statement behaves in a while loop.

Goes to the top of the loop and checks the condition.

Describe how a continue statement works in a for-loop

increments variable

Are String objects mutable or immutable?

immutable

Are Integer objects mutable?

no

Aliasing can lead to problems if the object is MUTABLE

True

Aliasing can lead to problems if the object is immutable

False

When passing an array of primitives to/from a method, is it safe to make a reference copy?

No, make a shallow copy.

How many ints are created by the statement: int[] a = new int[5]

5 ints; by default, 0

How many Strings are created by the statement: String[] a = new String[5]

Zero; Just null boxes

If you write a switch statement like this: switch(x) {...} What types could the variable x be?

int, short, byte, char, String

If you write a class without specifying a particular package, which package will it become part of?

default package

Another name for "parent" class

Superclass

What is a child of a parent class called?

Subclass

Declare an instance variable (a String called "y") in a way in which it will be visible ONLY in the class containing it.

private String y;

Declare an instance variable (a String called "x") in a way in which it will be visible everywhere in the project.

public String x;

Declare an instance variable (a String called "z") in a way in which it will be visible ONLY in classes that are in the same package as the class you are writing.

String z;

Make a copy constructor that references this constructor:

public Tomato (int diameter) {
this.diameter = diameter;
}

public Tomato (Tomato other) {
this(other.diameter);
}

What word describes an object whose state is initialized by a constructor, but then can never change any time after that?

Immutable