From 74df215f27d3292e09baa1a420bc57acfa9776e7 Mon Sep 17 00:00:00 2001
From: Jonathan Colmenares <jonathing.projects@gmail.com>
Date: Sat, 13 Feb 2021 14:36:50 -0500
Subject: [PATCH 1/4] slight structure cleanup

---
 .gitignore                   |  5 ++++-
 .idea/codeStyles/Project.xml |  6 ++++++
 .idea/misc.xml               |  8 ++++++++
 .idea/modules.xml            | 26 +++++++++++++-------------
 .idea/vcs.xml                |  5 +++++
 README.md                    |  4 ++--
 appa/Appendix A.iml          |  1 -
 appb/Appendix B.iml          |  1 -
 appc/Appendix C.iml          |  1 -
 appd/Appendix D.iml          |  1 -
 ch01/Chapter 1.iml           |  1 -
 ch02/Chapter 2.iml           |  1 -
 ch03/Chapter 3.iml           |  1 -
 ch04/Chapter 4.iml           |  1 -
 ch05/Chapter 5.iml           |  1 -
 ch06/Chapter 6.iml           |  1 -
 ch07/Chapter 7.iml           |  1 -
 ch08/Chapter 8.iml           |  1 -
 ch09/Chapter 9.iml           |  1 -
 ch10/Chapter 10.iml          |  1 -
 ch11/Chapter 11.iml          |  1 -
 ch12/Chapter 12.iml          |  1 -
 ch13/Chapter 13.iml          |  2 --
 ch14/Chapter 14.iml          |  1 -
 ch15/Chapter 15.iml          |  1 -
 ch16/Chapter 16.iml          |  1 -
 ch17/Chapter 17.iml          |  1 -
 27 files changed, 38 insertions(+), 38 deletions(-)
 create mode 100644 .idea/misc.xml

diff --git a/.gitignore b/.gitignore
index a423ea9..e4e5f5d 100644
--- a/.gitignore
+++ b/.gitignore
@@ -21,6 +21,9 @@ out/
 *.tar.gz
 *.rar
 
+# Libraries (Don't ignore)
+!junit-platform-console-standalone-*.jar
+
 # virtual machine crash logs, see http://www.java.com/en/download/help/error_hotspot.xml
 hs_err_pid*
 
@@ -35,8 +38,8 @@ hs_err_pid*
 .idea/**/dictionaries
 .idea/**/shelf
 .idea/**/hotswap_agent.xml
-.idea/**/misc.xml
 .idea/**/discord.xml
+.idea/**/markdown-nav*.xml
 
 # IntelliJ generated files
 .idea/**/contentModel.xml
diff --git a/.idea/codeStyles/Project.xml b/.idea/codeStyles/Project.xml
index 7f7b294..5f74459 100644
--- a/.idea/codeStyles/Project.xml
+++ b/.idea/codeStyles/Project.xml
@@ -1,6 +1,12 @@
 <component name="ProjectCodeStyleConfiguration">
   <code_scheme name="Project" version="173">
     <option name="RIGHT_MARGIN" value="80" />
+    <MarkdownNavigatorCodeStyleSettings>
+      <option name="RIGHT_MARGIN" value="72" />
+    </MarkdownNavigatorCodeStyleSettings>
+    <ScalaCodeStyleSettings>
+      <option name="MULTILINE_STRING_CLOSING_QUOTES_ON_NEW_LINE" value="true" />
+    </ScalaCodeStyleSettings>
     <codeStyleSettings language="JAVA">
       <option name="KEEP_LINE_BREAKS" value="false" />
       <option name="KEEP_FIRST_COLUMN_COMMENT" value="false" />
diff --git a/.idea/misc.xml b/.idea/misc.xml
new file mode 100644
index 0000000..a141913
--- /dev/null
+++ b/.idea/misc.xml
@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ASMPluginConfiguration">
+    <asm skipDebug="false" skipFrames="false" skipCode="false" expandFrames="false" />
+    <groovy codeStyle="LEGACY" />
+  </component>
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_11" default="true" project-jdk-name="11" project-jdk-type="JavaSDK" />
+</project>
\ No newline at end of file
diff --git a/.idea/modules.xml b/.idea/modules.xml
index 72a5052..36e0606 100644
--- a/.idea/modules.xml
+++ b/.idea/modules.xml
@@ -2,19 +2,7 @@
 <project version="4">
   <component name="ProjectModuleManager">
     <modules>
-      <module fileurl="file://$PROJECT_DIR$/appa/Appendix A.iml" filepath="$PROJECT_DIR$/appa/Appendix A.iml" />
-      <module fileurl="file://$PROJECT_DIR$/appb/Appendix B.iml" filepath="$PROJECT_DIR$/appb/Appendix B.iml" />
-      <module fileurl="file://$PROJECT_DIR$/appc/Appendix C.iml" filepath="$PROJECT_DIR$/appc/Appendix C.iml" />
-      <module fileurl="file://$PROJECT_DIR$/appd/Appendix D.iml" filepath="$PROJECT_DIR$/appd/Appendix D.iml" />
       <module fileurl="file://$PROJECT_DIR$/ch01/Chapter 1.iml" filepath="$PROJECT_DIR$/ch01/Chapter 1.iml" />
-      <module fileurl="file://$PROJECT_DIR$/ch10/Chapter 10.iml" filepath="$PROJECT_DIR$/ch10/Chapter 10.iml" />
-      <module fileurl="file://$PROJECT_DIR$/ch11/Chapter 11.iml" filepath="$PROJECT_DIR$/ch11/Chapter 11.iml" />
-      <module fileurl="file://$PROJECT_DIR$/ch12/Chapter 12.iml" filepath="$PROJECT_DIR$/ch12/Chapter 12.iml" />
-      <module fileurl="file://$PROJECT_DIR$/ch13/Chapter 13.iml" filepath="$PROJECT_DIR$/ch13/Chapter 13.iml" />
-      <module fileurl="file://$PROJECT_DIR$/ch14/Chapter 14.iml" filepath="$PROJECT_DIR$/ch14/Chapter 14.iml" />
-      <module fileurl="file://$PROJECT_DIR$/ch15/Chapter 15.iml" filepath="$PROJECT_DIR$/ch15/Chapter 15.iml" />
-      <module fileurl="file://$PROJECT_DIR$/ch16/Chapter 16.iml" filepath="$PROJECT_DIR$/ch16/Chapter 16.iml" />
-      <module fileurl="file://$PROJECT_DIR$/ch17/Chapter 17.iml" filepath="$PROJECT_DIR$/ch17/Chapter 17.iml" />
       <module fileurl="file://$PROJECT_DIR$/ch02/Chapter 2.iml" filepath="$PROJECT_DIR$/ch02/Chapter 2.iml" />
       <module fileurl="file://$PROJECT_DIR$/ch03/Chapter 3.iml" filepath="$PROJECT_DIR$/ch03/Chapter 3.iml" />
       <module fileurl="file://$PROJECT_DIR$/ch04/Chapter 4.iml" filepath="$PROJECT_DIR$/ch04/Chapter 4.iml" />
@@ -23,7 +11,19 @@
       <module fileurl="file://$PROJECT_DIR$/ch07/Chapter 7.iml" filepath="$PROJECT_DIR$/ch07/Chapter 7.iml" />
       <module fileurl="file://$PROJECT_DIR$/ch08/Chapter 8.iml" filepath="$PROJECT_DIR$/ch08/Chapter 8.iml" />
       <module fileurl="file://$PROJECT_DIR$/ch09/Chapter 9.iml" filepath="$PROJECT_DIR$/ch09/Chapter 9.iml" />
+      <module fileurl="file://$PROJECT_DIR$/ch10/Chapter 10.iml" filepath="$PROJECT_DIR$/ch10/Chapter 10.iml" />
+      <module fileurl="file://$PROJECT_DIR$/ch11/Chapter 11.iml" filepath="$PROJECT_DIR$/ch11/Chapter 11.iml" />
+      <module fileurl="file://$PROJECT_DIR$/ch12/Chapter 12.iml" filepath="$PROJECT_DIR$/ch12/Chapter 12.iml" />
+      <module fileurl="file://$PROJECT_DIR$/ch13/Chapter 13.iml" filepath="$PROJECT_DIR$/ch13/Chapter 13.iml" />
+      <module fileurl="file://$PROJECT_DIR$/ch14/Chapter 14.iml" filepath="$PROJECT_DIR$/ch14/Chapter 14.iml" />
+      <module fileurl="file://$PROJECT_DIR$/ch15/Chapter 15.iml" filepath="$PROJECT_DIR$/ch15/Chapter 15.iml" />
+      <module fileurl="file://$PROJECT_DIR$/ch16/Chapter 16.iml" filepath="$PROJECT_DIR$/ch16/Chapter 16.iml" />
+      <module fileurl="file://$PROJECT_DIR$/ch17/Chapter 17.iml" filepath="$PROJECT_DIR$/ch17/Chapter 17.iml" />
+      <module fileurl="file://$PROJECT_DIR$/appa/Appendix A.iml" filepath="$PROJECT_DIR$/appa/Appendix A.iml" />
+      <module fileurl="file://$PROJECT_DIR$/appb/Appendix B.iml" filepath="$PROJECT_DIR$/appb/Appendix B.iml" />
+      <module fileurl="file://$PROJECT_DIR$/appc/Appendix C.iml" filepath="$PROJECT_DIR$/appc/Appendix C.iml" />
+      <module fileurl="file://$PROJECT_DIR$/appd/Appendix D.iml" filepath="$PROJECT_DIR$/appd/Appendix D.iml" />
       <module fileurl="file://$PROJECT_DIR$/Think Java, 2nd Edition.iml" filepath="$PROJECT_DIR$/Think Java, 2nd Edition.iml" />
     </modules>
   </component>
-</project>
\ No newline at end of file
+</project>
diff --git a/.idea/vcs.xml b/.idea/vcs.xml
index 94a25f7..78cface 100644
--- a/.idea/vcs.xml
+++ b/.idea/vcs.xml
@@ -1,5 +1,10 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
+  <component name="CommitMessageInspectionProfile">
+    <profile version="1.0">
+      <inspection_tool class="GrazieCommit" enabled="true" level="TYPO" enabled_by_default="true" />
+    </profile>
+  </component>
   <component name="VcsDirectoryMappings">
     <mapping directory="$PROJECT_DIR$" vcs="Git" />
   </component>
diff --git a/README.md b/README.md
index b075769..7aa1bed 100644
--- a/README.md
+++ b/README.md
@@ -61,9 +61,9 @@ There are a few ways you can work with the code:
 
 ### IntelliJ IDEA
 
-[IntelliJ IDEA](https://www.jetbrains.com/idea/) is an IDE mainly used by professionals or ambitious beginners. It's not recommended for beginners to use this IDE due to how convoluted the user interface can be, but it is a great tool down the line of Java development.
+[IntelliJ IDEA](https://www.jetbrains.com/idea/) is an IDE mainly used by professionals or ambitious beginners. It's not recommended for beginners to use this IDE due to how convoluted the user interface can be, but it is a great tool down the line for Java development.
 
-- To open the source code in IntelliJ IDEA, open the `ThinkJavaCode2` folder as a project, as it has already been pre-configured as a project. Each of the chapter folders have been labeled as modules, so you can work with the code in each one as if they were a different project, similar to an Eclipse workspace. You do not need to worry about the `.checkstyle`, `.classpath`, or `.project` files.
+- To open the source code in IntelliJ IDEA, open the `ThinkJavaCode2` folder as a project, as it has already been pre-configured as a project. It should automatically use your installation of JDK 11. Each of the chapter folders have been labeled as modules, so you can work with the code in each one as if they were a different project, similar to an Eclipse workspace. You do not need to worry about the `.checkstyle`, `.classpath`, or `.project` files in each folder, and they are ignored by IntelliJ's build path.
 
 ### Visual Studio Code
 
diff --git a/appa/Appendix A.iml b/appa/Appendix A.iml
index 3766d77..3aabb4b 100644
--- a/appa/Appendix A.iml	
+++ b/appa/Appendix A.iml	
@@ -14,7 +14,6 @@
       <excludePattern pattern=".checkstyle" />
       <excludePattern pattern=".classpath" />
       <excludePattern pattern=".project" />
-      <excludePattern pattern="*.iml" />
     </content>
     <orderEntry type="inheritedJdk" />
     <orderEntry type="sourceFolder" forTests="false" />
diff --git a/appb/Appendix B.iml b/appb/Appendix B.iml
index 1b86140..ad5610a 100644
--- a/appb/Appendix B.iml	
+++ b/appb/Appendix B.iml	
@@ -14,7 +14,6 @@
       <excludePattern pattern=".checkstyle" />
       <excludePattern pattern=".classpath" />
       <excludePattern pattern=".project" />
-      <excludePattern pattern="*.iml" />
     </content>
     <orderEntry type="inheritedJdk" />
     <orderEntry type="sourceFolder" forTests="false" />
diff --git a/appc/Appendix C.iml b/appc/Appendix C.iml
index cda8616..4ee2204 100644
--- a/appc/Appendix C.iml	
+++ b/appc/Appendix C.iml	
@@ -14,7 +14,6 @@
       <excludePattern pattern=".checkstyle" />
       <excludePattern pattern=".classpath" />
       <excludePattern pattern=".project" />
-      <excludePattern pattern="*.iml" />
     </content>
     <orderEntry type="inheritedJdk" />
     <orderEntry type="sourceFolder" forTests="false" />
diff --git a/appd/Appendix D.iml b/appd/Appendix D.iml
index 8f708b7..8df396c 100644
--- a/appd/Appendix D.iml	
+++ b/appd/Appendix D.iml	
@@ -14,7 +14,6 @@
       <excludePattern pattern=".checkstyle" />
       <excludePattern pattern=".classpath" />
       <excludePattern pattern=".project" />
-      <excludePattern pattern="*.iml" />
     </content>
     <orderEntry type="inheritedJdk" />
     <orderEntry type="sourceFolder" forTests="false" />
diff --git a/ch01/Chapter 1.iml b/ch01/Chapter 1.iml
index 89db644..64e504e 100644
--- a/ch01/Chapter 1.iml	
+++ b/ch01/Chapter 1.iml	
@@ -14,7 +14,6 @@
       <excludePattern pattern=".checkstyle" />
       <excludePattern pattern=".classpath" />
       <excludePattern pattern=".project" />
-      <excludePattern pattern="*.iml" />
     </content>
     <orderEntry type="inheritedJdk" />
     <orderEntry type="sourceFolder" forTests="false" />
diff --git a/ch02/Chapter 2.iml b/ch02/Chapter 2.iml
index cff85c1..16bc5ba 100644
--- a/ch02/Chapter 2.iml	
+++ b/ch02/Chapter 2.iml	
@@ -14,7 +14,6 @@
       <excludePattern pattern=".checkstyle" />
       <excludePattern pattern=".classpath" />
       <excludePattern pattern=".project" />
-      <excludePattern pattern="*.iml" />
     </content>
     <orderEntry type="inheritedJdk" />
     <orderEntry type="sourceFolder" forTests="false" />
diff --git a/ch03/Chapter 3.iml b/ch03/Chapter 3.iml
index 111ffdc..348b482 100644
--- a/ch03/Chapter 3.iml	
+++ b/ch03/Chapter 3.iml	
@@ -14,7 +14,6 @@
       <excludePattern pattern=".checkstyle" />
       <excludePattern pattern=".classpath" />
       <excludePattern pattern=".project" />
-      <excludePattern pattern="*.iml" />
     </content>
     <orderEntry type="inheritedJdk" />
     <orderEntry type="sourceFolder" forTests="false" />
diff --git a/ch04/Chapter 4.iml b/ch04/Chapter 4.iml
index 307436c..fb2493a 100644
--- a/ch04/Chapter 4.iml	
+++ b/ch04/Chapter 4.iml	
@@ -14,7 +14,6 @@
       <excludePattern pattern=".checkstyle" />
       <excludePattern pattern=".classpath" />
       <excludePattern pattern=".project" />
-      <excludePattern pattern="*.iml" />
     </content>
     <orderEntry type="inheritedJdk" />
     <orderEntry type="sourceFolder" forTests="false" />
diff --git a/ch05/Chapter 5.iml b/ch05/Chapter 5.iml
index 053609f..e537f72 100644
--- a/ch05/Chapter 5.iml	
+++ b/ch05/Chapter 5.iml	
@@ -14,7 +14,6 @@
       <excludePattern pattern=".checkstyle" />
       <excludePattern pattern=".classpath" />
       <excludePattern pattern=".project" />
-      <excludePattern pattern="*.iml" />
     </content>
     <orderEntry type="inheritedJdk" />
     <orderEntry type="sourceFolder" forTests="false" />
diff --git a/ch06/Chapter 6.iml b/ch06/Chapter 6.iml
index 1103836..96345c0 100644
--- a/ch06/Chapter 6.iml	
+++ b/ch06/Chapter 6.iml	
@@ -14,7 +14,6 @@
       <excludePattern pattern=".checkstyle" />
       <excludePattern pattern=".classpath" />
       <excludePattern pattern=".project" />
-      <excludePattern pattern="*.iml" />
     </content>
     <orderEntry type="inheritedJdk" />
     <orderEntry type="sourceFolder" forTests="false" />
diff --git a/ch07/Chapter 7.iml b/ch07/Chapter 7.iml
index 37acecd..8e976ae 100644
--- a/ch07/Chapter 7.iml	
+++ b/ch07/Chapter 7.iml	
@@ -14,7 +14,6 @@
       <excludePattern pattern=".checkstyle" />
       <excludePattern pattern=".classpath" />
       <excludePattern pattern=".project" />
-      <excludePattern pattern="*.iml" />
     </content>
     <orderEntry type="inheritedJdk" />
     <orderEntry type="sourceFolder" forTests="false" />
diff --git a/ch08/Chapter 8.iml b/ch08/Chapter 8.iml
index 696ab43..d599502 100644
--- a/ch08/Chapter 8.iml	
+++ b/ch08/Chapter 8.iml	
@@ -14,7 +14,6 @@
       <excludePattern pattern=".checkstyle" />
       <excludePattern pattern=".classpath" />
       <excludePattern pattern=".project" />
-      <excludePattern pattern="*.iml" />
     </content>
     <orderEntry type="inheritedJdk" />
     <orderEntry type="sourceFolder" forTests="false" />
diff --git a/ch09/Chapter 9.iml b/ch09/Chapter 9.iml
index 10c13c1..56ffcff 100644
--- a/ch09/Chapter 9.iml	
+++ b/ch09/Chapter 9.iml	
@@ -14,7 +14,6 @@
       <excludePattern pattern=".checkstyle" />
       <excludePattern pattern=".classpath" />
       <excludePattern pattern=".project" />
-      <excludePattern pattern="*.iml" />
     </content>
     <orderEntry type="inheritedJdk" />
     <orderEntry type="sourceFolder" forTests="false" />
diff --git a/ch10/Chapter 10.iml b/ch10/Chapter 10.iml
index b49c4b0..afc3cda 100644
--- a/ch10/Chapter 10.iml	
+++ b/ch10/Chapter 10.iml	
@@ -14,7 +14,6 @@
       <excludePattern pattern=".checkstyle" />
       <excludePattern pattern=".classpath" />
       <excludePattern pattern=".project" />
-      <excludePattern pattern="*.iml" />
     </content>
     <orderEntry type="inheritedJdk" />
     <orderEntry type="sourceFolder" forTests="false" />
diff --git a/ch11/Chapter 11.iml b/ch11/Chapter 11.iml
index 08ba565..c4ddb15 100644
--- a/ch11/Chapter 11.iml	
+++ b/ch11/Chapter 11.iml	
@@ -14,7 +14,6 @@
       <excludePattern pattern=".checkstyle" />
       <excludePattern pattern=".classpath" />
       <excludePattern pattern=".project" />
-      <excludePattern pattern="*.iml" />
     </content>
     <orderEntry type="inheritedJdk" />
     <orderEntry type="sourceFolder" forTests="false" />
diff --git a/ch12/Chapter 12.iml b/ch12/Chapter 12.iml
index 0a23653..c4e0f77 100644
--- a/ch12/Chapter 12.iml	
+++ b/ch12/Chapter 12.iml	
@@ -15,7 +15,6 @@
       <excludePattern pattern=".checkstyle" />
       <excludePattern pattern=".classpath" />
       <excludePattern pattern=".project" />
-      <excludePattern pattern="*.iml" />
     </content>
     <orderEntry type="inheritedJdk" />
     <orderEntry type="sourceFolder" forTests="false" />
diff --git a/ch13/Chapter 13.iml b/ch13/Chapter 13.iml
index 663eb2f..871edd4 100644
--- a/ch13/Chapter 13.iml	
+++ b/ch13/Chapter 13.iml	
@@ -11,11 +11,9 @@
     <exclude-output />
     <content url="file://$MODULE_DIR$">
       <sourceFolder url="file://$MODULE_DIR$" isTestSource="false" />
-      <sourceFolder url="file://$MODULE_DIR$/src" isTestSource="false" />
       <excludePattern pattern=".checkstyle" />
       <excludePattern pattern=".classpath" />
       <excludePattern pattern=".project" />
-      <excludePattern pattern="*.iml" />
     </content>
     <orderEntry type="jdk" jdkName="11" jdkType="JavaSDK" />
     <orderEntry type="sourceFolder" forTests="false" />
diff --git a/ch14/Chapter 14.iml b/ch14/Chapter 14.iml
index f46e317..c692174 100644
--- a/ch14/Chapter 14.iml	
+++ b/ch14/Chapter 14.iml	
@@ -14,7 +14,6 @@
       <excludePattern pattern=".checkstyle" />
       <excludePattern pattern=".classpath" />
       <excludePattern pattern=".project" />
-      <excludePattern pattern="*.iml" />
     </content>
     <orderEntry type="inheritedJdk" />
     <orderEntry type="sourceFolder" forTests="false" />
diff --git a/ch15/Chapter 15.iml b/ch15/Chapter 15.iml
index fbba225..fc70802 100644
--- a/ch15/Chapter 15.iml	
+++ b/ch15/Chapter 15.iml	
@@ -14,7 +14,6 @@
       <excludePattern pattern=".checkstyle" />
       <excludePattern pattern=".classpath" />
       <excludePattern pattern=".project" />
-      <excludePattern pattern="*.iml" />
     </content>
     <orderEntry type="inheritedJdk" />
     <orderEntry type="sourceFolder" forTests="false" />
diff --git a/ch16/Chapter 16.iml b/ch16/Chapter 16.iml
index 9cfdead..3109edb 100644
--- a/ch16/Chapter 16.iml	
+++ b/ch16/Chapter 16.iml	
@@ -14,7 +14,6 @@
       <excludePattern pattern=".checkstyle" />
       <excludePattern pattern=".classpath" />
       <excludePattern pattern=".project" />
-      <excludePattern pattern="*.iml" />
     </content>
     <orderEntry type="inheritedJdk" />
     <orderEntry type="sourceFolder" forTests="false" />
diff --git a/ch17/Chapter 17.iml b/ch17/Chapter 17.iml
index 0486ccb..fb4a474 100644
--- a/ch17/Chapter 17.iml	
+++ b/ch17/Chapter 17.iml	
@@ -14,7 +14,6 @@
       <excludePattern pattern=".checkstyle" />
       <excludePattern pattern=".classpath" />
       <excludePattern pattern=".project" />
-      <excludePattern pattern="*.iml" />
     </content>
     <orderEntry type="inheritedJdk" />
     <orderEntry type="sourceFolder" forTests="false" />

From fb44802784fd7d56a580ba8f83d3186ab72ece84 Mon Sep 17 00:00:00 2001
From: Jonathan Colmenares <jonathing.projects@gmail.com>
Date: Sat, 13 Feb 2021 14:37:09 -0500
Subject: [PATCH 2/4] added settings for CheckStyle-IDEA plugin

---
 .gitignore                | 1 +
 .idea/checkstyle-idea.xml | 2 ++
 README.md                 | 4 +++-
 3 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/.gitignore b/.gitignore
index e4e5f5d..b70b3e2 100644
--- a/.gitignore
+++ b/.gitignore
@@ -40,6 +40,7 @@ hs_err_pid*
 .idea/**/hotswap_agent.xml
 .idea/**/discord.xml
 .idea/**/markdown-nav*.xml
+.idea/**/checkstyleidea-libs/
 
 # IntelliJ generated files
 .idea/**/contentModel.xml
diff --git a/.idea/checkstyle-idea.xml b/.idea/checkstyle-idea.xml
index fea3990..12f0957 100644
--- a/.idea/checkstyle-idea.xml
+++ b/.idea/checkstyle-idea.xml
@@ -3,10 +3,12 @@
   <component name="CheckStyle-IDEA">
     <option name="configuration">
       <map>
+        <entry key="active-configuration" value="PROJECT_RELATIVE:$PROJECT_DIR$/Checkstyle.xml:Think Java, 2nd Edition" />
         <entry key="checkstyle-version" value="8.36.2" />
         <entry key="copy-libs" value="true" />
         <entry key="location-0" value="BUNDLED:(bundled):Sun Checks" />
         <entry key="location-1" value="BUNDLED:(bundled):Google Checks" />
+        <entry key="location-2" value="PROJECT_RELATIVE:$PROJECT_DIR$/Checkstyle.xml:Think Java, 2nd Edition" />
         <entry key="scan-before-checkin" value="false" />
         <entry key="scanscope" value="JavaOnly" />
         <entry key="suppress-errors" value="false" />
diff --git a/README.md b/README.md
index 7aa1bed..e952f18 100644
--- a/README.md
+++ b/README.md
@@ -57,13 +57,15 @@ There are a few ways you can work with the code:
 
 [Eclipse](https://www.eclipse.org/) is another IDE used by beginners and professionals alike, and is more feature-rich than jGRASP.
 
-- To open the source code in Eclipse, change your workspace to the `ThinkJavaCode2` folder. Eclipse should automatically detect the different chapter folders as projects and should add them accordingly. You do not need to worry about the `*.iml` file in each folder.
+- To open the source code in Eclipse, change your workspace to the `ThinkJavaCode2` folder. Eclipse should automatically detect the different chapter folders as projects and should add them accordingly. You do not need to worry about the `*.iml`
+- If you want to use CheckStyle with these projects, feel free to install the official [Eclipse Checkstyle Plugin](https://checkstyle.org/eclipse-cs/#!/) and then use the `Checkstyle.xml` file in the root folder as the configuration file.
 
 ### IntelliJ IDEA
 
 [IntelliJ IDEA](https://www.jetbrains.com/idea/) is an IDE mainly used by professionals or ambitious beginners. It's not recommended for beginners to use this IDE due to how convoluted the user interface can be, but it is a great tool down the line for Java development.
 
 - To open the source code in IntelliJ IDEA, open the `ThinkJavaCode2` folder as a project, as it has already been pre-configured as a project. It should automatically use your installation of JDK 11. Each of the chapter folders have been labeled as modules, so you can work with the code in each one as if they were a different project, similar to an Eclipse workspace. You do not need to worry about the `.checkstyle`, `.classpath`, or `.project` files in each folder, and they are ignored by IntelliJ's build path.
+- If you want to use CheckStyle with these projects, feel free to install the [CheckStyle-IDEA](https://plugins.jetbrains.com/plugin/1065-checkstyle-idea) plugin into your project (Settings -> Plugins). The settings for this project have already been pre-configured and should be recognized automatically when you restart your IDE to enable the plugin.
 
 ### Visual Studio Code
 

From f4713d069a1fb201826068dab95652845e930192 Mon Sep 17 00:00:00 2001
From: rl1m <rlim.email@gmail.com>
Date: Wed, 9 Nov 2022 19:14:02 +0100
Subject: [PATCH 3/4] Add exercise chapter 3

---
 ch03/exercises/CelsiusToFahrenheit.java | 21 +++++++++++++++++
 ch03/exercises/GuessMyNumber.java       | 31 +++++++++++++++++++++++++
 ch03/exercises/SecondsConverter.java    | 24 +++++++++++++++++++
 3 files changed, 76 insertions(+)
 create mode 100644 ch03/exercises/CelsiusToFahrenheit.java
 create mode 100644 ch03/exercises/GuessMyNumber.java
 create mode 100644 ch03/exercises/SecondsConverter.java

diff --git a/ch03/exercises/CelsiusToFahrenheit.java b/ch03/exercises/CelsiusToFahrenheit.java
new file mode 100644
index 0000000..6e48916
--- /dev/null
+++ b/ch03/exercises/CelsiusToFahrenheit.java
@@ -0,0 +1,21 @@
+package exercises;
+
+import java.util.Scanner;
+
+public class CelsiusToFahrenheit {
+
+    public static void main(String[] args) {
+        double celsius;
+        double fahrenheit;
+        Scanner in = new Scanner(System.in);
+
+        System.out.print("Enter a temperature in Celcius: ");
+        celsius = in.nextDouble();
+        fahrenheit = toFahrenheit(celsius);
+        System.out.printf("%.1f C = %.1f\n", celsius, fahrenheit);
+    }
+
+    public static double toFahrenheit(double celsius) {
+        return (celsius * 9) / 5.0 + 32;
+    }
+}
diff --git a/ch03/exercises/GuessMyNumber.java b/ch03/exercises/GuessMyNumber.java
new file mode 100644
index 0000000..1f2d0c3
--- /dev/null
+++ b/ch03/exercises/GuessMyNumber.java
@@ -0,0 +1,31 @@
+package exercises;
+
+import java.util.Random;
+import java.util.Scanner;
+
+public class GuessMyNumber {
+    private final static int MAX_NUMBER = 100;
+
+    public static void main(String[] args) {
+        int guess;
+        int answer = getRandomNumber();
+
+        Scanner in = new Scanner(System.in);
+
+        System.out.println("I'm thinking of a number between 1 and 100");
+        System.out.println("(including both). Can you guess what it is?");
+        System.out.print("Type a number: ");
+
+        guess = in.nextInt();
+        in.nextLine();
+
+        System.out.printf("Your guess is: %d\n", guess);
+        System.out.printf("The number I was thinking of is: %d\n", answer);
+        System.out.printf("You were off by: %d\n", Math.abs(guess - answer));
+    }
+
+    private static int getRandomNumber() {
+        Random random = new Random();
+        return random.nextInt(MAX_NUMBER) + 1;
+    }
+}
diff --git a/ch03/exercises/SecondsConverter.java b/ch03/exercises/SecondsConverter.java
new file mode 100644
index 0000000..a073372
--- /dev/null
+++ b/ch03/exercises/SecondsConverter.java
@@ -0,0 +1,24 @@
+package exercises;
+
+import java.util.Scanner;
+
+public class SecondsConverter {
+    public static final int SECOND_PER_HOUR = 3600;
+    private static final int SECOND_PER_MINUTE = 60;
+
+    public static void main(String[] args) {
+        int totalSeconds;
+        Scanner in = new Scanner(System.in);
+
+        System.out.print("How many seconds? ");
+        totalSeconds = in.nextInt();
+        in.nextLine();
+
+        int hours = totalSeconds / SECOND_PER_HOUR;
+        int minutes = (totalSeconds % SECOND_PER_HOUR) / SECOND_PER_MINUTE;
+        int seconds = totalSeconds % SECOND_PER_MINUTE;
+
+        System.out.printf("%d seconds = %d hours, %d minutes, and %d seconds\n",
+                totalSeconds, hours, minutes, seconds);
+    }
+}

From 6d83275b627ef10f37fe5087b28929eccda44032 Mon Sep 17 00:00:00 2001
From: rl1m <rlim.email@gmail.com>
Date: Sat, 12 Nov 2022 16:12:04 +0100
Subject: [PATCH 4/4] Add answer

---
 ch04/MultAdd.java | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)
 create mode 100644 ch04/MultAdd.java

diff --git a/ch04/MultAdd.java b/ch04/MultAdd.java
new file mode 100644
index 0000000..df97f2c
--- /dev/null
+++ b/ch04/MultAdd.java
@@ -0,0 +1,29 @@
+public class MultAdd {
+    public static void main(String[] args) {
+        multadd(1.0, 2.0, 3.0);
+
+        double a1 = Math.sin(Math.PI / 4);
+        double b1 = Math.cos(Math.PI / 4);
+        double c1 = 0.5;
+        multadd(a1, b1, c1);
+
+        double a2 = Math.log(10);
+        double b2 = Math.log(20);
+        double c2 = 1.0;
+        multadd(a2, b2, c2);
+
+        expSum(1);
+    }
+
+    public static void multadd(double a, double b, double c){
+        double result = a * b + c;
+        System.out.println(result);
+    }
+
+    public static void expSum(double x){
+        double a = x;
+        double b = Math.exp(-x);
+        double c = Math.sqrt(1 - b);
+        multadd(a, b , c);
+    }
+}