Java Development in Eclipse

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Questions and Answers

What must be included in the multi-line comment block at the top of each source code file?

Program version and last compiled date

My full name and professor's name

Description of the program and environment setup

All of the above (correct)

Where are .java files located after creating a project in Eclipse?

bin folder

src folder (correct)

documents folder

api folder

What is the default file extension for UMLet diagrams?

.uxf (correct)

.class

.java

.txt

Which perspective in Eclipse is used for editing and compiling code?

Java perspective Signup and view all the answers

How do you add a horizontal line in a UML Class Diagram in UMLet?

Enter two hyphens in the properties for the diagram Signup and view all the answers

Is there an installer for Eclipse after downloading and extracting the installer?

No, it is a standalone application Signup and view all the answers

What is the difference between double and Double?

double is a primitive type, Double is a wrapper class Signup and view all the answers

What folder does Eclipse use to store all projects?

workspace Signup and view all the answers

What data type does the format specifier %d work with?

int Signup and view all the answers

During the hybrid 2 activity, what was the output of a specific program?

0.9999999999999999 Signup and view all the answers

What does %n do when used in a format String?

Writes an operating system appropriate line terminator into the output Signup and view all the answers

How do you set a breakpoint in Eclipse?

Double click on the grey margin on the left side of the source code view Signup and view all the answers

In UMLet, what type of diagram are we currently learning to use?

UML Class Diagram Signup and view all the answers

Who created Git?

Linux Torvalds and the Linux community Signup and view all the answers

What is Git?

Git is a distributed (local and remote) version control system Signup and view all the answers

What is the Git command git init used for?

To create a new repository Signup and view all the answers

What is the primary purpose of adding a file to the staging area in Git?

To take a snapshot of the file that has changes Signup and view all the answers

Where are reference types (objects) stored in memory during program execution?

Heap Signup and view all the answers

What does a method call within the Method Call Stack refer to?

Stack frame Signup and view all the answers

Which setting is recommended for the HOME system environment variable when working with Git in Windows?

%USERPROFILE% Signup and view all the answers

To start tracking changes to project files in Eclipse, what submenu should be used?

Team > Add to Index Signup and view all the answers

Which project folder should be included in the .gitignore settings file?

/bin/ Signup and view all the answers

What is the primary use of the Heap in memory management?

Storing reference types (objects) Signup and view all the answers

After modifying a source code file, how do you commit the changes with Git in Eclipse?

Right-click and select Team > Commit Signup and view all the answers

What is placed into the box representing a variable of a reference-type that does not reference an object?

null Signup and view all the answers

What is placed into the box representing a variable of a primitive type?

the literal value Signup and view all the answers

Are Strings in Java classified as a reference type?

yes Signup and view all the answers

When memory mapping a reference type, what notation is used to annotate the class name?

{ and } Signup and view all the answers

What representation is used to illustrate array elements in memory mapping?

a column, or row of contiguous boxes Signup and view all the answers

What would a memory map look like for the code 'Sheep[] sheeps = null'?

A box with null in it Signup and view all the answers

For the code 'Sheep[] sheeps = new Sheep[2];', what does the memory map illustrate?

A variable with ref pointing to an array, but each element is null Signup and view all the answers

Given 'Sheep[] sheeps = { new Sheep(), new Sheep() };', how is this represented in memory mapping?

A variable with ref pointing to an array with initialized Sheep objects Signup and view all the answers

What is the outcome of writing 'Sheep[] sheeps = new Sheep[200000];' when 'sheeps' is not initialized?

A syntax error occurs due to the empty array. Signup and view all the answers

Which statement accurately describes the memory map of 'Sheep[] sheeps = new Sheep[200000];'?

The memory map will show an array object with null in each element. Signup and view all the answers

What should constructors avoid in terms of console input/output?

Including print statements during object instantiation. Signup and view all the answers

Why is it advisable to avoid using static for every variable or method?

Static usage restricts the multi-instance capabilities of classes. Signup and view all the answers

What design problem is associated with the createReport() method in class orange?

It performs excessive tasks that confuse functionality. Signup and view all the answers

What is the benefit of marking fields as private?

It protects the class from unintended external modifications. Signup and view all the answers

What is a consequence of not using 'this' in static methods?

It leads to ambiguity in variable access. Signup and view all the answers

What should be avoided when using accessors and mutators?

Including user input through console. Signup and view all the answers

Study Notes

Multi-line Comment Block Requirements

Include full name and professor's name
Include due date and last modified date
Include a description of the program
All of the above

Eclipse Project Structure

Java files are located in the src folder within the project.
documents, bin, and api folders are also part of the project structure.

Eclipse Development Environment

To edit and compile code in Eclipse, use the Java perspective.

Eclipse Installer

The Eclipse installer does not include a separate installer program.

Eclipse Project Storage

Projects are stored in the workspace.

Hybrid 2 Activity Output

The output of the hybrid 2 activity program is 1.0.
Values that were not assigned as expected: Actual: 0.7999999999999999, Expected: 0.8 Values that were not assigned as expected: Actual: 0.30000000000000004, Expected: 0.3

Debugging in Eclipse

Resume: Runs the program.
Red Terminate: Ends the program.
Step Over: Executes the next line of the current method.

Setting Breakpoints in Eclipse

Double-click the grey margin in the left side of the source code view, or
Right-click on the grey margin and select "Toggle breakpoint".

UML Diagram Types

UML Class Diagram
UML Sequence Diagram
UML Activity Diagram
UML Deployment Diagram

UML Class Diagram Template

Simple Class.

UML Diagram File Extension

.uxf

Adding Horizontal Lines in UML Class Diagrams

Use hyphens in the properties of the diagram, then hit enter.

Primitive vs. Wrapper Classes

double is a primitive data type, and Double is a wrapper class.

Format Specifier Usage

%s: works with String
%d: works with int
%f: works with double

Git

It tracks changes made to files.
Can be local and remote.
git init: Creates a new repository.
git commit: Used to create snapshots of changes made.
When you need to stage file changes, you use git add to prepare files that have changed for commitment and use git commit to save those changes.

Method Call Stack

Used to store information about methods and their data during program execution.

Heap Memory

Used to store reference types, like objects.

Memory Mapping

Primitive types: store their literal values.
Reference types: store a reference to the object's location in memory

Memory Map for Sheep Array (null):

Show variable sheeps with a reference to a null pointer

Studying That Suits You

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Description

Test your knowledge on setting up and managing Java projects in the Eclipse IDE. This quiz covers everything from project structure to debugging practices. Perfect for students learning Java development or preparing for exams.