diff --git a/.github/workflows/check_lesson_16_java_pr.yaml b/.github/workflows/check_lesson_16_java_pr.yaml
new file mode 100644
index 000000000..acc8fc06a
--- /dev/null
+++ b/.github/workflows/check_lesson_16_java_pr.yaml
@@ -0,0 +1,28 @@
+name: Check Lesson 16 Java Pull Request
+
+on:
+  pull_request:
+    branches: [ "main" ]
+    paths:
+      - "lesson_16/objects/**"
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      pull-requests: write
+
+    steps:
+    - uses: actions/checkout@v4
+
+    - name: Set up JDK
+      uses: actions/setup-java@v4
+      with:
+        java-version: '21'
+        distribution: 'temurin'
+
+    - name: Build Lesson 16 with Java
+      working-directory: ./lesson_16/objects
+      run: ./gradlew check
\ No newline at end of file
diff --git a/lesson_16/README.md b/lesson_16/README.md
index c74d71867..8425d736e 100644
--- a/lesson_16/README.md
+++ b/lesson_16/README.md
@@ -10,5 +10,26 @@ Please review the following resources before lecture:
 
 ## Homework
 
-- TODO(anthonydmays): Add details here
+- [ ] Complete [Custom Data Types](#custom-data-types) assignment.
+- [ ] Do pre-work for [lesson 17](/lesson_17/).
+
+## Custom Data Types
+
+For this assignment, you will need to pull together everything that you've learned up to this point to design and create your own data types. Again, remember to use the [Conventional Commits][conventional-commits] spec for your commit messages and pull requests.
+
+1. Create a sub-folder in the main [app folder][lesson16-folder] with a unique name for your work.
+2. Design at least one custom class that represents a real-world object.
+    * The class must have at least 5 member variables of at least 3 different types. One of the member variables must be a collection type (Array, ArrayList, etc.).
+    * You must also incorporate an enum type as well.
+    * The class must have at least one constructor.
+    * The class must have at least 3 member functions.
+    * One of your functions must make use of a conditional expression.
+    * One of your functions must make use of your collection member variable.
+    * One of your functions must make use of a loop.
+    * You must use at least one custom exception.
+3. Create a matching subfolder in the [test folder][test-folder] and a test file. Your test must include at least 5 test methods.
+
+[lesson16-folder]: ./objects/objects_app/src/main/java/com/codedifferently/lesson16/
+[test-folder]: ./objects/objects_app/src/test/java/com/codedifferently/lesson16/
+[conventional-commits]: https://www.conventionalcommits.org/en/v3.0.0/
 
diff --git a/lesson_16/objects/.gitattributes b/lesson_16/objects/.gitattributes
new file mode 100644
index 000000000..097f9f98d
--- /dev/null
+++ b/lesson_16/objects/.gitattributes
@@ -0,0 +1,9 @@
+#
+# https://help.github.com/articles/dealing-with-line-endings/
+#
+# Linux start script should use lf
+/gradlew        text eol=lf
+
+# These are Windows script files and should use crlf
+*.bat           text eol=crlf
+
diff --git a/lesson_16/objects/.gitignore b/lesson_16/objects/.gitignore
new file mode 100644
index 000000000..1b6985c00
--- /dev/null
+++ b/lesson_16/objects/.gitignore
@@ -0,0 +1,5 @@
+# Ignore Gradle project-specific cache directory
+.gradle
+
+# Ignore Gradle build output directory
+build
diff --git a/lesson_16/objects/gradle/wrapper/gradle-wrapper.jar b/lesson_16/objects/gradle/wrapper/gradle-wrapper.jar
new file mode 100644
index 000000000..a4b76b953
Binary files /dev/null and b/lesson_16/objects/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/lesson_16/objects/gradle/wrapper/gradle-wrapper.properties b/lesson_16/objects/gradle/wrapper/gradle-wrapper.properties
new file mode 100644
index 000000000..e2847c820
--- /dev/null
+++ b/lesson_16/objects/gradle/wrapper/gradle-wrapper.properties
@@ -0,0 +1,7 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.11.1-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
diff --git a/lesson_16/objects/gradlew b/lesson_16/objects/gradlew
new file mode 100755
index 000000000..f5feea6d6
--- /dev/null
+++ b/lesson_16/objects/gradlew
@@ -0,0 +1,252 @@
+#!/bin/sh
+
+#
+# Copyright © 2015-2021 the original authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+
+##############################################################################
+#
+#   Gradle start up script for POSIX generated by Gradle.
+#
+#   Important for running:
+#
+#   (1) You need a POSIX-compliant shell to run this script. If your /bin/sh is
+#       noncompliant, but you have some other compliant shell such as ksh or
+#       bash, then to run this script, type that shell name before the whole
+#       command line, like:
+#
+#           ksh Gradle
+#
+#       Busybox and similar reduced shells will NOT work, because this script
+#       requires all of these POSIX shell features:
+#         * functions;
+#         * expansions «$var», «${var}», «${var:-default}», «${var+SET}»,
+#           «${var#prefix}», «${var%suffix}», and «$( cmd )»;
+#         * compound commands having a testable exit status, especially «case»;
+#         * various built-in commands including «command», «set», and «ulimit».
+#
+#   Important for patching:
+#
+#   (2) This script targets any POSIX shell, so it avoids extensions provided
+#       by Bash, Ksh, etc; in particular arrays are avoided.
+#
+#       The "traditional" practice of packing multiple parameters into a
+#       space-separated string is a well documented source of bugs and security
+#       problems, so this is (mostly) avoided, by progressively accumulating
+#       options in "$@", and eventually passing that to Java.
+#
+#       Where the inherited environment variables (DEFAULT_JVM_OPTS, JAVA_OPTS,
+#       and GRADLE_OPTS) rely on word-splitting, this is performed explicitly;
+#       see the in-line comments for details.
+#
+#       There are tweaks for specific operating systems such as AIX, CygWin,
+#       Darwin, MinGW, and NonStop.
+#
+#   (3) This script is generated from the Groovy template
+#       https://github.com/gradle/gradle/blob/HEAD/platforms/jvm/plugins-application/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       within the Gradle project.
+#
+#       You can find Gradle at https://github.com/gradle/gradle/.
+#
+##############################################################################
+
+# Attempt to set APP_HOME
+
+# Resolve links: $0 may be a link
+app_path=$0
+
+# Need this for daisy-chained symlinks.
+while
+    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+    [ -h "$app_path" ]
+do
+    ls=$( ls -ld "$app_path" )
+    link=${ls#*' -> '}
+    case $link in             #(
+      /*)   app_path=$link ;; #(
+      *)    app_path=$APP_HOME$link ;;
+    esac
+done
+
+# This is normally unused
+# shellcheck disable=SC2034
+APP_BASE_NAME=${0##*/}
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd -P "${APP_HOME:-./}" > /dev/null && printf '%s
+' "$PWD" ) || exit
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD=maximum
+
+warn () {
+    echo "$*"
+} >&2
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+} >&2
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "$( uname )" in                #(
+  CYGWIN* )         cygwin=true  ;; #(
+  Darwin* )         darwin=true  ;; #(
+  MSYS* | MINGW* )  msys=true    ;; #(
+  NONSTOP* )        nonstop=true ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD=$JAVA_HOME/jre/sh/java
+    else
+        JAVACMD=$JAVA_HOME/bin/java
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD=java
+    if ! command -v java >/dev/null 2>&1
+    then
+        die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+fi
+
+# Increase the maximum file descriptors if we can.
+if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
+    case $MAX_FD in #(
+      max*)
+        # In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC2039,SC3045
+        MAX_FD=$( ulimit -H -n ) ||
+            warn "Could not query maximum file descriptor limit"
+    esac
+    case $MAX_FD in  #(
+      '' | soft) :;; #(
+      *)
+        # In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC2039,SC3045
+        ulimit -n "$MAX_FD" ||
+            warn "Could not set maximum file descriptor limit to $MAX_FD"
+    esac
+fi
+
+# Collect all arguments for the java command, stacking in reverse order:
+#   * args from the command line
+#   * the main class name
+#   * -classpath
+#   * -D...appname settings
+#   * --module-path (only if needed)
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and GRADLE_OPTS environment variables.
+
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if "$cygwin" || "$msys" ; then
+    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+
+    JAVACMD=$( cygpath --unix "$JAVACMD" )
+
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    for arg do
+        if
+            case $arg in                                #(
+              -*)   false ;;                            # don't mess with options #(
+              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+                    [ -e "$t" ] ;;                      #(
+              *)    false ;;
+            esac
+        then
+            arg=$( cygpath --path --ignore --mixed "$arg" )
+        fi
+        # Roll the args list around exactly as many times as the number of
+        # args, so each arg winds up back in the position where it started, but
+        # possibly modified.
+        #
+        # NB: a `for` loop captures its iteration list before it begins, so
+        # changing the positional parameters here affects neither the number of
+        # iterations, nor the values presented in `arg`.
+        shift                   # remove old arg
+        set -- "$@" "$arg"      # push replacement arg
+    done
+fi
+
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
+
+set -- \
+        "-Dorg.gradle.appname=$APP_BASE_NAME" \
+        -classpath "$CLASSPATH" \
+        org.gradle.wrapper.GradleWrapperMain \
+        "$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+    die "xargs is not available"
+fi
+
+# Use "xargs" to parse quoted args.
+#
+# With -n1 it outputs one arg per line, with the quotes and backslashes removed.
+#
+# In Bash we could simply go:
+#
+#   readarray ARGS < <( xargs -n1 <<<"$var" ) &&
+#   set -- "${ARGS[@]}" "$@"
+#
+# but POSIX shell has neither arrays nor command substitution, so instead we
+# post-process each arg (as a line of input to sed) to backslash-escape any
+# character that might be a shell metacharacter, then use eval to reverse
+# that process (while maintaining the separation between arguments), and wrap
+# the whole thing up as a single "set" statement.
+#
+# This will of course break if any of these variables contains a newline or
+# an unmatched quote.
+#
+
+eval "set -- $(
+        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+        xargs -n1 |
+        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+        tr '\n' ' '
+    )" '"$@"'
+
+exec "$JAVACMD" "$@"
diff --git a/lesson_16/objects/gradlew.bat b/lesson_16/objects/gradlew.bat
new file mode 100644
index 000000000..9d21a2183
--- /dev/null
+++ b/lesson_16/objects/gradlew.bat
@@ -0,0 +1,94 @@
+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+@rem SPDX-License-Identifier: Apache-2.0
+@rem
+
+@if "%DEBUG%"=="" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if %ERRORLEVEL% equ 0 goto execute
+
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto execute
+
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
+
+goto fail
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %*
+
+:end
+@rem End local scope for the variables with windows NT shell
+if %ERRORLEVEL% equ 0 goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega
diff --git a/lesson_16/objects/objects_app/build.gradle.kts b/lesson_16/objects/objects_app/build.gradle.kts
new file mode 100644
index 000000000..460529b07
--- /dev/null
+++ b/lesson_16/objects/objects_app/build.gradle.kts
@@ -0,0 +1,84 @@
+plugins {
+    // Apply the application plugin to add support for building a CLI application in Java.
+    application
+    eclipse
+    jacoco
+    id("io.freefair.lombok") version "8.10.2"
+    id("com.diffplug.spotless") version "6.25.0"
+	  id("org.springframework.boot") version "3.4.0"
+    id("com.adarshr.test-logger") version "4.0.0"
+}
+
+apply(plugin = "io.spring.dependency-management")
+
+repositories {
+    // Use Maven Central for resolving dependencies.
+    mavenCentral()
+}
+
+dependencies {
+    // Use JUnit Jupiter for testing.
+    testImplementation("org.junit.jupiter:junit-jupiter:5.11.3")
+    testImplementation("org.springframework.boot:spring-boot-starter-test")
+    testImplementation("org.assertj:assertj-core:3.26.3")
+    testImplementation("at.favre.lib:bcrypt:0.10.2")
+
+    // This dependency is used by the application.
+    implementation("com.google.guava:guava:33.3.1-jre")
+    implementation("com.google.code.gson:gson:2.11.0")
+    implementation("org.springframework.boot:spring-boot-starter")
+}
+
+application {
+    // Define the main class for the application.
+    mainClass.set("com.codedifferently.lesson16.Lesson16")
+}
+
+tasks.named<Test>("test") {
+    // Use JUnit Platform for unit tests.
+    useJUnitPlatform()
+    finalizedBy(tasks.jacocoTestReport)
+}
+
+tasks.jacocoTestReport {
+  dependsOn(tasks.test)
+  reports {
+    xml.required = true
+  }
+}
+
+tasks.jacocoTestCoverageVerification {
+  violationRules {
+    rule {
+      limit {
+        minimum = "0.8".toBigDecimal()
+      }
+    }
+  }
+}
+
+tasks.check {
+	dependsOn(tasks.jacocoTestCoverageVerification)
+}
+
+configure<com.diffplug.gradle.spotless.SpotlessExtension> {
+
+  format("misc", {
+    // define the files to apply `misc` to
+    target("*.gradle", ".gitattributes", ".gitignore")
+
+    // define the steps to apply to those files
+    trimTrailingWhitespace()
+    indentWithTabs() // or spaces. Takes an integer argument if you don't like 4
+    endWithNewline()
+  })
+
+  java {
+    // don't need to set target, it is inferred from java
+
+    // apply a specific flavor of google-java-format
+    googleJavaFormat()
+    // fix formatting of type annotations
+    formatAnnotations()
+  }
+}
diff --git a/lesson_16/objects/objects_app/src/main/java/com/codedifferently/lesson16/Lesson16.java b/lesson_16/objects/objects_app/src/main/java/com/codedifferently/lesson16/Lesson16.java
new file mode 100644
index 000000000..fd5348f09
--- /dev/null
+++ b/lesson_16/objects/objects_app/src/main/java/com/codedifferently/lesson16/Lesson16.java
@@ -0,0 +1,15 @@
+package com.codedifferently.lesson16;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.context.annotation.Configuration;
+
+@Configuration
+@SpringBootApplication(scanBasePackages = "com.codedifferently")
+public class Lesson16 {
+
+  public static void main(String[] args) {
+    var application = new SpringApplication(Lesson16.class);
+    application.run(args);
+  }
+}
diff --git a/lesson_16/objects/objects_app/src/test/java/com/codedifferently/lesson16/Lesson16Test.java b/lesson_16/objects/objects_app/src/test/java/com/codedifferently/lesson16/Lesson16Test.java
new file mode 100644
index 000000000..2032de832
--- /dev/null
+++ b/lesson_16/objects/objects_app/src/test/java/com/codedifferently/lesson16/Lesson16Test.java
@@ -0,0 +1,15 @@
+package com.codedifferently.lesson16;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.boot.test.context.SpringBootTest;
+
+@SpringBootTest(useMainMethod = SpringBootTest.UseMainMethod.WHEN_AVAILABLE)
+class Lesson16Test {
+
+  @Test
+  void testMain() {
+    assertThat(new Lesson16()).isNotNull();
+  }
+}
diff --git a/lesson_16/objects/settings.gradle.kts b/lesson_16/objects/settings.gradle.kts
new file mode 100644
index 000000000..124a25863
--- /dev/null
+++ b/lesson_16/objects/settings.gradle.kts
@@ -0,0 +1,11 @@
+/*
+ * This file was generated by the Gradle 'init' task.
+ *
+ * The settings file is used to specify which projects to include in your build.
+ *
+ * Detailed information about configuring a multi-project build in Gradle can be found
+ * in the user manual at https://docs.gradle.org/8.0.2/userguide/multi_project_builds.html
+ */
+
+rootProject.name = "lesson_16"
+include("objects_app")
diff --git a/lesson_17/README.md b/lesson_17/README.md
new file mode 100644
index 000000000..9c1718058
--- /dev/null
+++ b/lesson_17/README.md
@@ -0,0 +1,19 @@
+# Lesson 17: OOP Principles, Part II ([Slides](https://code-differently.github.io/code-differently-25-q1/slides/#/lesson_17))
+
+## Pre-work
+
+Please review the following resources before lecture:
+
+### Required
+
+* [Object-oriented Programming in 7 minutes | Mosh (Video)](https://www.youtube.com/watch?v=pTB0EiLXUC8)
+* [Naming Convention In Java Tutorial #77 (Video)](https://www.youtube.com/watch?v=QazDDPtSulY)
+
+### Recommended
+
+* [Naming Conventions - Oracle (Article)](https://www.oracle.com/java/technologies/javase/codeconventions-namingconventions.html)
+* [Test-Driven Development (TDD): A Time-Tested Recipe for Quality Software (Article)](https://semaphoreci.com/blog/test-driven-development)
+
+## Homework
+
+- TODO(anthonydmays): Make 'em work!!!
\ No newline at end of file