diff --git a/.github/workflows/check_lesson_17_java_pr.yaml b/.github/workflows/check_lesson_17_java_pr.yaml
new file mode 100644
index 000000000..367e0e09a
--- /dev/null
+++ b/.github/workflows/check_lesson_17_java_pr.yaml
@@ -0,0 +1,28 @@
+name: Check Lesson 17 Java Pull Request
+
+on:
+  pull_request:
+    branches: [ "main" ]
+    paths:
+      - "lesson_17/bank/**"
+
+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 17 with Java
+      working-directory: ./lesson_17/bank
+      run: ./gradlew check
\ No newline at end of file
diff --git a/.github/workflows/check_push.yml b/.github/workflows/check_push.yml
index c3ad4b188..054de1e25 100644
--- a/.github/workflows/check_push.yml
+++ b/.github/workflows/check_push.yml
@@ -19,6 +19,10 @@ on:
       - "lesson_12/structs_ts/**"
       - "lesson_13/maps_java/**"
       - "lesson_13/maps_ts/**"
+      - "lesson_14/exceptions/**"
+      - "lesson_15/tdd/**"
+      - "lesson_16/objects/**"
+      - "lesson_17/bank/**"
 jobs:
   build:
     runs-on: ubuntu-latest
@@ -141,3 +145,22 @@ jobs:
       run: |
         npm ci
         npm run compile
+        
+    - name: Build Lesson 14 with Java
+      working-directory: ./lesson_14/exceptions
+      run: ./gradlew assemble
+
+    - name: Build Lesson 15 with Java
+      working-directory: ./lesson_15/tdd
+      run: |
+        ./gradlew assemble
+        ./gradlew spotlessCheck
+
+    - name: Build Lesson 16 with Java
+      working-directory: ./lesson_16/objects
+      run: ./gradlew check
+
+    - name: Build Lesson 17 with Java
+      working-directory: ./lesson_17/bank
+      run: ./gradlew check
+
diff --git a/lesson_17/README.md b/lesson_17/README.md
index 9c1718058..142fb57c3 100644
--- a/lesson_17/README.md
+++ b/lesson_17/README.md
@@ -16,4 +16,27 @@ Please review the following resources before lecture:
 
 ## Homework
 
-- TODO(anthonydmays): Make 'em work!!!
\ No newline at end of file
+- [ ] Complete [Applying SOLID principles](#applying-solid-principles-bank-atm) exercise.
+- [ ] Review [OOP Project](/project_oop/) documentation and complete user stories.
+
+## Applying SOLID Principles (Bank ATM)
+
+Your task for this assignment is add enhancements to an ATM simulator. The [BankAtm][bankatm-file] is at the center of the model, allowing us to add one or more `CheckingAccount` instances and make withdrawals or deposits via cash or check. You will need to implement at least two of the following functional enhancements to the `BankAtm` class WITHOUT adding a new method. Note that you can update existing methods, however.
+
+### Functional Requirements
+
+* We want to support a `SavingsAccount` that works just like the `CheckingAccount`, but doesn't allow you to write checks against the account.
+* We want the `BankAtm` class to support the concept of a `BusinessCheckingAccount`. A business account requires that at least one of the owning accounts is a business.
+* In addition to supporting checks and cash, we also want to support the concept of another monetary instrument called a `MoneyOrder`. Unlike a `Check`, a `MoneyOrder` withdraws funds from a source account immediately on creation for the purposes of this simulation..
+* For traceability, all of the transactions in the `BankAtm` class should logged. Create an `AuditLog` class that keeps a record of all debits and credits to any account and integrate it with the `BankAtm` class. 
+* ~~For the `depositFunds` method that accepts a cash amount, we'd like the ability to deposit funds in a variety of currencies. Add a parameter that accepts a currency type and a new object that encapsulates the currency converter logic for converting a cash amount to the account currency type.~~
+
+### Technical Requirements
+
+* You must integrate new features into the `BankAtm` without adding a new public method. Existing public methods may be modified without breaking existing functionality.
+* You must update the `BankAtm` tests and may modify or add other applicable tests.
+* Feel free to add the minimal number of classes, interfaces, or abstract classes needed to fulfill each requirement.
+* You must update existing javadocs and may add new documentation for new types and methods you introduce.
+
+[bank-folder]: ./bank/
+[bankatm-file]: ./bank/bank_app/src/main/java/com/codedifferently/lesson17/bank/BankAtm.java
\ No newline at end of file
diff --git a/lesson_17/bank/.gitattributes b/lesson_17/bank/.gitattributes
new file mode 100644
index 000000000..097f9f98d
--- /dev/null
+++ b/lesson_17/bank/.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_17/bank/.gitignore b/lesson_17/bank/.gitignore
new file mode 100644
index 000000000..1b6985c00
--- /dev/null
+++ b/lesson_17/bank/.gitignore
@@ -0,0 +1,5 @@
+# Ignore Gradle project-specific cache directory
+.gradle
+
+# Ignore Gradle build output directory
+build
diff --git a/lesson_17/bank/bank_app/build.gradle.kts b/lesson_17/bank/bank_app/build.gradle.kts
new file mode 100644
index 000000000..5f768d848
--- /dev/null
+++ b/lesson_17/bank/bank_app/build.gradle.kts
@@ -0,0 +1,85 @@
+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.projectlombok:lombok:1.18.30")
+    implementation("org.springframework.boot:spring-boot-starter")
+}
+
+application {
+    // Define the main class for the application.
+    mainClass.set("com.codedifferently.lesson17.Lesson17")
+}
+
+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_17/bank/bank_app/src/main/java/com/codedifferently/lesson17/Lesson17.java b/lesson_17/bank/bank_app/src/main/java/com/codedifferently/lesson17/Lesson17.java
new file mode 100644
index 000000000..c11084e57
--- /dev/null
+++ b/lesson_17/bank/bank_app/src/main/java/com/codedifferently/lesson17/Lesson17.java
@@ -0,0 +1,15 @@
+package com.codedifferently.lesson17;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.context.annotation.Configuration;
+
+@Configuration
+@SpringBootApplication(scanBasePackages = "com.codedifferently")
+public class Lesson17 {
+
+  public static void main(String[] args) {
+    var application = new SpringApplication(Lesson17.class);
+    application.run(args);
+  }
+}
diff --git a/lesson_17/bank/bank_app/src/main/java/com/codedifferently/lesson17/bank/BankAtm.java b/lesson_17/bank/bank_app/src/main/java/com/codedifferently/lesson17/bank/BankAtm.java
new file mode 100644
index 000000000..8cbcd3cc0
--- /dev/null
+++ b/lesson_17/bank/bank_app/src/main/java/com/codedifferently/lesson17/bank/BankAtm.java
@@ -0,0 +1,88 @@
+package com.codedifferently.lesson17.bank;
+
+import com.codedifferently.lesson17.bank.exceptions.AccountNotFoundException;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Set;
+import java.util.UUID;
+
+/** Represents a bank ATM. */
+public class BankAtm {
+
+  private final Map<UUID, Customer> customerById = new HashMap<>();
+  private final Map<String, CheckingAccount> accountByNumber = new HashMap<>();
+
+  /**
+   * Adds a checking account to the bank.
+   *
+   * @param account The account to add.
+   */
+  public void addAccount(CheckingAccount account) {
+    accountByNumber.put(account.getAccountNumber(), account);
+    account
+        .getOwners()
+        .forEach(
+            owner -> {
+              customerById.put(owner.getId(), owner);
+            });
+  }
+
+  /**
+   * Finds all accounts owned by a customer.
+   *
+   * @param customerId The ID of the customer.
+   * @return The unique set of accounts owned by the customer.
+   */
+  public Set<CheckingAccount> findAccountsByCustomerId(UUID customerId) {
+    return customerById.containsKey(customerId)
+        ? customerById.get(customerId).getAccounts()
+        : Set.of();
+  }
+
+  /**
+   * Deposits funds into an account.
+   *
+   * @param accountNumber The account number.
+   * @param amount The amount to deposit.
+   */
+  public void depositFunds(String accountNumber, double amount) {
+    CheckingAccount account = getAccountOrThrow(accountNumber);
+    account.deposit(amount);
+  }
+
+  /**
+   * Deposits funds into an account using a check.
+   *
+   * @param accountNumber The account number.
+   * @param check The check to deposit.
+   */
+  public void depositFunds(String accountNumber, Check check) {
+    CheckingAccount account = getAccountOrThrow(accountNumber);
+    check.depositFunds(account);
+  }
+
+  /**
+   * Withdraws funds from an account.
+   *
+   * @param accountNumber
+   * @param amount
+   */
+  public void withdrawFunds(String accountNumber, double amount) {
+    CheckingAccount account = getAccountOrThrow(accountNumber);
+    account.withdraw(amount);
+  }
+
+  /**
+   * Gets an account by its number or throws an exception if not found.
+   *
+   * @param accountNumber The account number.
+   * @return The account.
+   */
+  private CheckingAccount getAccountOrThrow(String accountNumber) {
+    CheckingAccount account = accountByNumber.get(accountNumber);
+    if (account == null || account.isClosed()) {
+      throw new AccountNotFoundException("Account not found");
+    }
+    return account;
+  }
+}
diff --git a/lesson_17/bank/bank_app/src/main/java/com/codedifferently/lesson17/bank/Check.java b/lesson_17/bank/bank_app/src/main/java/com/codedifferently/lesson17/bank/Check.java
new file mode 100644
index 000000000..061fa4a5c
--- /dev/null
+++ b/lesson_17/bank/bank_app/src/main/java/com/codedifferently/lesson17/bank/Check.java
@@ -0,0 +1,82 @@
+package com.codedifferently.lesson17.bank;
+
+import com.codedifferently.lesson17.bank.exceptions.CheckVoidedException;
+
+/** Represents a check. */
+public class Check {
+
+  private final String checkNumber;
+  private final double amount;
+  private final CheckingAccount account;
+  private boolean isVoided = false;
+
+  /**
+   * Creates a new check.
+   *
+   * @param checkNumber The check number.
+   * @param amount The amount of the check.
+   * @param account The account the check is drawn on.
+   */
+  public Check(String checkNumber, double amount, CheckingAccount account) {
+    if (amount < 0) {
+      throw new IllegalArgumentException("Check amount must be positive");
+    }
+    this.checkNumber = checkNumber;
+    this.amount = amount;
+    this.account = account;
+  }
+
+  /**
+   * Gets the voided status of the check.
+   *
+   * @return True if the check is voided, and false otherwise.
+   */
+  public boolean getIsVoided() {
+    return isVoided;
+  }
+
+  /** Voids the check. */
+  public void voidCheck() {
+    isVoided = true;
+  }
+
+  /**
+   * Deposits the check into an account.
+   *
+   * @param toAccount The account to deposit the check into.
+   */
+  public void depositFunds(CheckingAccount toAccount) {
+    if (isVoided) {
+      throw new CheckVoidedException("Check is voided");
+    }
+    account.withdraw(amount);
+    toAccount.deposit(amount);
+    voidCheck();
+  }
+
+  @Override
+  public int hashCode() {
+    return checkNumber.hashCode();
+  }
+
+  @Override
+  public boolean equals(Object obj) {
+    if (obj instanceof Check other) {
+      return checkNumber.equals(other.checkNumber);
+    }
+    return false;
+  }
+
+  @Override
+  public String toString() {
+    return "Check{"
+        + "checkNumber='"
+        + checkNumber
+        + '\''
+        + ", amount="
+        + amount
+        + ", account="
+        + account.getAccountNumber()
+        + '}';
+  }
+}
diff --git a/lesson_17/bank/bank_app/src/main/java/com/codedifferently/lesson17/bank/CheckingAccount.java b/lesson_17/bank/bank_app/src/main/java/com/codedifferently/lesson17/bank/CheckingAccount.java
new file mode 100644
index 000000000..5d8aeb74d
--- /dev/null
+++ b/lesson_17/bank/bank_app/src/main/java/com/codedifferently/lesson17/bank/CheckingAccount.java
@@ -0,0 +1,131 @@
+package com.codedifferently.lesson17.bank;
+
+import com.codedifferently.lesson17.bank.exceptions.InsufficientFundsException;
+import java.util.Set;
+
+/** Represents a checking account. */
+public class CheckingAccount {
+
+  private final Set<Customer> owners;
+  private final String accountNumber;
+  private double balance;
+  private boolean isActive;
+
+  /**
+   * Creates a new checking account.
+   *
+   * @param accountNumber The account number.
+   * @param owners The owners of the account.
+   * @param initialBalance The initial balance of the account.
+   */
+  public CheckingAccount(String accountNumber, Set<Customer> owners, double initialBalance) {
+    this.accountNumber = accountNumber;
+    this.owners = owners;
+    this.balance = initialBalance;
+    isActive = true;
+  }
+
+  /**
+   * Gets the account number.
+   *
+   * @return The account number.
+   */
+  public String getAccountNumber() {
+    return accountNumber;
+  }
+
+  /**
+   * Gets the owners of the account.
+   *
+   * @return The owners of the account.
+   */
+  public Set<Customer> getOwners() {
+    return owners;
+  }
+
+  /**
+   * Deposits funds into the account.
+   *
+   * @param amount The amount to deposit.
+   */
+  public void deposit(double amount) throws IllegalStateException {
+    if (isClosed()) {
+      throw new IllegalStateException("Cannot deposit to a closed account");
+    }
+    if (amount <= 0) {
+      throw new IllegalArgumentException("Deposit amount must be positive");
+    }
+    balance += amount;
+  }
+
+  /**
+   * Withdraws funds from the account.
+   *
+   * @param amount
+   * @throws InsufficientFundsException
+   */
+  public void withdraw(double amount) throws InsufficientFundsException {
+    if (isClosed()) {
+      throw new IllegalStateException("Cannot withdraw from a closed account");
+    }
+    if (amount <= 0) {
+      throw new IllegalStateException("Withdrawal amount must be positive");
+    }
+    if (balance < amount) {
+      throw new InsufficientFundsException("Account does not have enough funds for withdrawal");
+    }
+    balance -= amount;
+  }
+
+  /**
+   * Gets the balance of the account.
+   *
+   * @return The balance of the account.
+   */
+  public double getBalance() {
+    return balance;
+  }
+
+  /** Closes the account. */
+  public void closeAccount() throws IllegalStateException {
+    if (balance > 0) {
+      throw new IllegalStateException("Cannot close account with a positive balance");
+    }
+    isActive = false;
+  }
+
+  /**
+   * Checks if the account is closed.
+   *
+   * @return True if the account is closed, otherwise false.
+   */
+  public boolean isClosed() {
+    return !isActive;
+  }
+
+  @Override
+  public int hashCode() {
+    return accountNumber.hashCode();
+  }
+
+  @Override
+  public boolean equals(Object obj) {
+    if (obj instanceof CheckingAccount other) {
+      return accountNumber.equals(other.accountNumber);
+    }
+    return false;
+  }
+
+  @Override
+  public String toString() {
+    return "CheckingAccount{"
+        + "accountNumber='"
+        + accountNumber
+        + '\''
+        + ", balance="
+        + balance
+        + ", isActive="
+        + isActive
+        + '}';
+  }
+}
diff --git a/lesson_17/bank/bank_app/src/main/java/com/codedifferently/lesson17/bank/Customer.java b/lesson_17/bank/bank_app/src/main/java/com/codedifferently/lesson17/bank/Customer.java
new file mode 100644
index 000000000..af0847134
--- /dev/null
+++ b/lesson_17/bank/bank_app/src/main/java/com/codedifferently/lesson17/bank/Customer.java
@@ -0,0 +1,78 @@
+package com.codedifferently.lesson17.bank;
+
+import java.util.HashSet;
+import java.util.Set;
+import java.util.UUID;
+
+/** Represents a customer of the bank. */
+public class Customer {
+
+  private final UUID id;
+  private final String name;
+  private final Set<CheckingAccount> accounts = new HashSet<>();
+
+  /**
+   * Creates a new customer.
+   *
+   * @param id The ID of the customer.
+   * @param name The name of the customer.
+   */
+  public Customer(UUID id, String name) {
+    this.id = id;
+    this.name = name;
+  }
+
+  /**
+   * Gets the ID of the customer.
+   *
+   * @return The ID of the customer.
+   */
+  public UUID getId() {
+    return id;
+  }
+
+  /**
+   * Gets the name of the customer.
+   *
+   * @return The name of the customer.
+   */
+  public String getName() {
+    return name;
+  }
+
+  /**
+   * Adds a checking account to the customer.
+   *
+   * @param account The account to add.
+   */
+  public void addAccount(CheckingAccount account) {
+    accounts.add(account);
+  }
+
+  /**
+   * Gets the accounts owned by the customer.
+   *
+   * @return The unique set of accounts owned by the customer.
+   */
+  public Set<CheckingAccount> getAccounts() {
+    return accounts;
+  }
+
+  @Override
+  public int hashCode() {
+    return id.hashCode();
+  }
+
+  @Override
+  public boolean equals(Object obj) {
+    if (obj instanceof Customer other) {
+      return id.equals(other.id);
+    }
+    return false;
+  }
+
+  @Override
+  public String toString() {
+    return "Customer{" + "id=" + id + ", name='" + name + '\'' + '}';
+  }
+}
diff --git a/lesson_17/bank/bank_app/src/main/java/com/codedifferently/lesson17/bank/exceptions/AccountNotFoundException.java b/lesson_17/bank/bank_app/src/main/java/com/codedifferently/lesson17/bank/exceptions/AccountNotFoundException.java
new file mode 100644
index 000000000..b03386e17
--- /dev/null
+++ b/lesson_17/bank/bank_app/src/main/java/com/codedifferently/lesson17/bank/exceptions/AccountNotFoundException.java
@@ -0,0 +1,10 @@
+package com.codedifferently.lesson17.bank.exceptions;
+
+public class AccountNotFoundException extends RuntimeException {
+
+  public AccountNotFoundException() {}
+
+  public AccountNotFoundException(String message) {
+    super(message);
+  }
+}
diff --git a/lesson_17/bank/bank_app/src/main/java/com/codedifferently/lesson17/bank/exceptions/CheckVoidedException.java b/lesson_17/bank/bank_app/src/main/java/com/codedifferently/lesson17/bank/exceptions/CheckVoidedException.java
new file mode 100644
index 000000000..d51443d4a
--- /dev/null
+++ b/lesson_17/bank/bank_app/src/main/java/com/codedifferently/lesson17/bank/exceptions/CheckVoidedException.java
@@ -0,0 +1,10 @@
+package com.codedifferently.lesson17.bank.exceptions;
+
+public class CheckVoidedException extends RuntimeException {
+
+  public CheckVoidedException() {}
+
+  public CheckVoidedException(String message) {
+    super(message);
+  }
+}
diff --git a/lesson_17/bank/bank_app/src/main/java/com/codedifferently/lesson17/bank/exceptions/InsufficientFundsException.java b/lesson_17/bank/bank_app/src/main/java/com/codedifferently/lesson17/bank/exceptions/InsufficientFundsException.java
new file mode 100644
index 000000000..75de59329
--- /dev/null
+++ b/lesson_17/bank/bank_app/src/main/java/com/codedifferently/lesson17/bank/exceptions/InsufficientFundsException.java
@@ -0,0 +1,10 @@
+package com.codedifferently.lesson17.bank.exceptions;
+
+public class InsufficientFundsException extends RuntimeException {
+
+  public InsufficientFundsException() {}
+
+  public InsufficientFundsException(String message) {
+    super(message);
+  }
+}
diff --git a/lesson_17/bank/bank_app/src/test/java/com/codedifferently/lesson17/Lesson17Test.java b/lesson_17/bank/bank_app/src/test/java/com/codedifferently/lesson17/Lesson17Test.java
new file mode 100644
index 000000000..1579e4bf9
--- /dev/null
+++ b/lesson_17/bank/bank_app/src/test/java/com/codedifferently/lesson17/Lesson17Test.java
@@ -0,0 +1,16 @@
+package com.codedifferently.lesson17;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.test.context.SpringBootTest.UseMainMethod;
+
+@SpringBootTest(useMainMethod = UseMainMethod.WHEN_AVAILABLE)
+class Lesson17Test {
+
+  @Test
+  void testInstantiate() {
+    assertThat(new Lesson17()).isNotNull();
+  }
+}
diff --git a/lesson_17/bank/bank_app/src/test/java/com/codedifferently/lesson17/bank/BankAtmTest.java b/lesson_17/bank/bank_app/src/test/java/com/codedifferently/lesson17/bank/BankAtmTest.java
new file mode 100644
index 000000000..fa4a913a2
--- /dev/null
+++ b/lesson_17/bank/bank_app/src/test/java/com/codedifferently/lesson17/bank/BankAtmTest.java
@@ -0,0 +1,110 @@
+package com.codedifferently.lesson17.bank;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
+
+import com.codedifferently.lesson17.bank.exceptions.AccountNotFoundException;
+import com.codedifferently.lesson17.bank.exceptions.CheckVoidedException;
+import java.util.Set;
+import java.util.UUID;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+class BankAtmTest {
+
+  private BankAtm classUnderTest;
+  private CheckingAccount account1;
+  private CheckingAccount account2;
+  private Customer customer1;
+  private Customer customer2;
+
+  @BeforeEach
+  void setUp() {
+    classUnderTest = new BankAtm();
+    customer1 = new Customer(UUID.randomUUID(), "John Doe");
+    customer2 = new Customer(UUID.randomUUID(), "Jane Smith");
+    account1 = new CheckingAccount("123456789", Set.of(customer1), 100.0);
+    account2 = new CheckingAccount("987654321", Set.of(customer1, customer2), 200.0);
+    customer1.addAccount(account1);
+    customer1.addAccount(account2);
+    customer2.addAccount(account2);
+    classUnderTest.addAccount(account1);
+    classUnderTest.addAccount(account2);
+  }
+
+  @Test
+  void testAddAccount() {
+    // Arrange
+    Customer customer3 = new Customer(UUID.randomUUID(), "Alice Johnson");
+    CheckingAccount account3 = new CheckingAccount("555555555", Set.of(customer3), 300.0);
+    customer3.addAccount(account3);
+
+    // Act
+    classUnderTest.addAccount(account3);
+
+    // Assert
+    Set<CheckingAccount> accounts = classUnderTest.findAccountsByCustomerId(customer3.getId());
+    assertThat(accounts).containsOnly(account3);
+  }
+
+  @Test
+  void testFindAccountsByCustomerId() {
+    // Act
+    Set<CheckingAccount> accounts = classUnderTest.findAccountsByCustomerId(customer1.getId());
+
+    // Assert
+    assertThat(accounts).containsOnly(account1, account2);
+  }
+
+  @Test
+  void testDepositFunds() {
+    // Act
+    classUnderTest.depositFunds(account1.getAccountNumber(), 50.0);
+
+    // Assert
+    assertThat(account1.getBalance()).isEqualTo(150.0);
+  }
+
+  @Test
+  void testDepositFunds_Check() {
+    // Arrange
+    Check check = new Check("987654321", 100.0, account1);
+
+    // Act
+    classUnderTest.depositFunds("987654321", check);
+
+    // Assert
+    assertThat(account1.getBalance()).isEqualTo(0);
+    assertThat(account2.getBalance()).isEqualTo(300.0);
+  }
+
+  @Test
+  void testDepositFunds_DoesntDepositCheckTwice() {
+    Check check = new Check("987654321", 100.0, account1);
+
+    classUnderTest.depositFunds("987654321", check);
+
+    assertThatExceptionOfType(CheckVoidedException.class)
+        .isThrownBy(() -> classUnderTest.depositFunds("987654321", check))
+        .withMessage("Check is voided");
+  }
+
+  @Test
+  void testWithdrawFunds() {
+    // Act
+    classUnderTest.withdrawFunds(account2.getAccountNumber(), 50.0);
+
+    // Assert
+    assertThat(account2.getBalance()).isEqualTo(150.0);
+  }
+
+  @Test
+  void testWithdrawFunds_AccountNotFound() {
+    String nonExistingAccountNumber = "999999999";
+
+    // Act & Assert
+    assertThatExceptionOfType(AccountNotFoundException.class)
+        .isThrownBy(() -> classUnderTest.withdrawFunds(nonExistingAccountNumber, 50.0))
+        .withMessage("Account not found");
+  }
+}
diff --git a/lesson_17/bank/bank_app/src/test/java/com/codedifferently/lesson17/bank/CheckTest.java b/lesson_17/bank/bank_app/src/test/java/com/codedifferently/lesson17/bank/CheckTest.java
new file mode 100644
index 000000000..6b62d39ba
--- /dev/null
+++ b/lesson_17/bank/bank_app/src/test/java/com/codedifferently/lesson17/bank/CheckTest.java
@@ -0,0 +1,78 @@
+package com.codedifferently.lesson17.bank;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
+
+import com.codedifferently.lesson17.bank.exceptions.CheckVoidedException;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+class CheckTest {
+
+  private CheckingAccount account1;
+  private CheckingAccount account2;
+  private Check classUnderTest;
+
+  @BeforeEach
+  void setUp() {
+    account1 = new CheckingAccount("123456789", null, 100.0);
+    account2 = new CheckingAccount("987654321", null, 200.0);
+    classUnderTest = new Check("123456789", 50.0, account1);
+  }
+
+  @Test
+  void testDepositFunds() {
+    // Act
+    classUnderTest.depositFunds(account2);
+
+    // Assert
+    assertThat(account1.getBalance()).isEqualTo(50.0);
+    assertThat(account2.getBalance()).isEqualTo(250.0);
+  }
+
+  @Test
+  void testDepositFunds_CheckVoided() {
+    // Arrange
+    classUnderTest.voidCheck();
+
+    // Act & Assert
+    assertThatExceptionOfType(CheckVoidedException.class)
+        .isThrownBy(() -> classUnderTest.depositFunds(account2))
+        .withMessage("Check is voided");
+  }
+
+  @Test
+  void testConstructor_CantCreateCheckWithNegativeAmount() {
+    // Act & Assert
+    assertThatExceptionOfType(IllegalArgumentException.class)
+        .isThrownBy(() -> new Check("123456789", -50.0, account1))
+        .withMessage("Check amount must be positive");
+  }
+
+  @Test
+  void testHashCode() {
+    // Arrange
+    Check otherCheck = new Check("123456789", 100.0, account1);
+
+    // Assert
+    assertThat(classUnderTest.hashCode()).isEqualTo(otherCheck.hashCode());
+  }
+
+  @Test
+  void testEquals() {
+    // Arrange
+    Check otherCheck = new Check("123456789", 100.0, account1);
+    Check differentCheck = new Check("987654321", 100.0, account1);
+
+    // Assert
+    assertThat(classUnderTest.equals(otherCheck)).isTrue();
+    assertThat(classUnderTest.equals(differentCheck)).isFalse();
+  }
+
+  @Test
+  void testToString() {
+    // Assert
+    assertThat(classUnderTest.toString())
+        .isEqualTo("Check{checkNumber='123456789', amount=50.0, account=123456789}");
+  }
+}
diff --git a/lesson_17/bank/bank_app/src/test/java/com/codedifferently/lesson17/bank/CheckingAccountTest.java b/lesson_17/bank/bank_app/src/test/java/com/codedifferently/lesson17/bank/CheckingAccountTest.java
new file mode 100644
index 000000000..f155d8e5b
--- /dev/null
+++ b/lesson_17/bank/bank_app/src/test/java/com/codedifferently/lesson17/bank/CheckingAccountTest.java
@@ -0,0 +1,106 @@
+package com.codedifferently.lesson17.bank;
+
+import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import com.codedifferently.lesson17.bank.exceptions.InsufficientFundsException;
+import java.util.HashSet;
+import java.util.Set;
+import java.util.UUID;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+class CheckingAccountTest {
+
+  private CheckingAccount classUnderTest;
+  private Set<Customer> owners;
+
+  @BeforeEach
+  void setUp() {
+    owners = new HashSet<>();
+    owners.add(new Customer(UUID.randomUUID(), "John Doe"));
+    owners.add(new Customer(UUID.randomUUID(), "Jane Smith"));
+    classUnderTest = new CheckingAccount("123456789", owners, 100.0);
+  }
+
+  @Test
+  void getAccountNumber() {
+    assertEquals("123456789", classUnderTest.getAccountNumber());
+  }
+
+  @Test
+  void getOwners() {
+    assertEquals(owners, classUnderTest.getOwners());
+  }
+
+  @Test
+  void deposit() {
+    classUnderTest.deposit(50.0);
+    assertEquals(150.0, classUnderTest.getBalance());
+  }
+
+  @Test
+  void deposit_withNegativeAmount() {
+    assertThatExceptionOfType(IllegalArgumentException.class)
+        .isThrownBy(() -> classUnderTest.deposit(-50.0));
+  }
+
+  @Test
+  void withdraw() {
+    classUnderTest.withdraw(50.0);
+    assertEquals(50.0, classUnderTest.getBalance());
+  }
+
+  @Test
+  void withdraw_withNegativeAmount() {
+    assertThatExceptionOfType(IllegalStateException.class)
+        .isThrownBy(() -> classUnderTest.withdraw(-50.0))
+        .withMessage("Withdrawal amount must be positive");
+  }
+
+  @Test
+  void withdraw_withInsufficientBalance() {
+    assertThatExceptionOfType(InsufficientFundsException.class)
+        .isThrownBy(() -> classUnderTest.withdraw(150.0))
+        .withMessage("Account does not have enough funds for withdrawal");
+  }
+
+  @Test
+  void getBalance() {
+    assertEquals(100.0, classUnderTest.getBalance());
+  }
+
+  @Test
+  void closeAccount_withPositiveBalance() {
+    assertThatExceptionOfType(IllegalStateException.class)
+        .isThrownBy(() -> classUnderTest.closeAccount());
+  }
+
+  @Test
+  void isClosed() {
+    assertFalse(classUnderTest.isClosed());
+    classUnderTest.withdraw(100);
+    classUnderTest.closeAccount();
+    assertTrue(classUnderTest.isClosed());
+  }
+
+  @Test
+  void equals() {
+    CheckingAccount otherAccount = new CheckingAccount("123456789", owners, 200.0);
+    assertEquals(classUnderTest, otherAccount);
+  }
+
+  @Test
+  void hashCodeTest() {
+    CheckingAccount otherAccount = new CheckingAccount("123456789", owners, 200.0);
+    assertEquals(classUnderTest.hashCode(), otherAccount.hashCode());
+  }
+
+  @Test
+  void toStringTest() {
+    String expected = "CheckingAccount{accountNumber='123456789', balance=100.0, isActive=true}";
+    assertEquals(expected, classUnderTest.toString());
+  }
+}
diff --git a/lesson_17/bank/gradle/wrapper/gradle-wrapper.jar b/lesson_17/bank/gradle/wrapper/gradle-wrapper.jar
new file mode 100644
index 000000000..a4b76b953
Binary files /dev/null and b/lesson_17/bank/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/lesson_17/bank/gradle/wrapper/gradle-wrapper.properties b/lesson_17/bank/gradle/wrapper/gradle-wrapper.properties
new file mode 100644
index 000000000..e2847c820
--- /dev/null
+++ b/lesson_17/bank/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_17/bank/gradlew b/lesson_17/bank/gradlew
new file mode 100755
index 000000000..f5feea6d6
--- /dev/null
+++ b/lesson_17/bank/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_17/bank/gradlew.bat b/lesson_17/bank/gradlew.bat
new file mode 100644
index 000000000..9d21a2183
--- /dev/null
+++ b/lesson_17/bank/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_17/bank/settings.gradle.kts b/lesson_17/bank/settings.gradle.kts
new file mode 100644
index 000000000..e921324fe
--- /dev/null
+++ b/lesson_17/bank/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_13"
+include("bank_app")
diff --git a/lesson_21/README.md b/lesson_21/README.md
new file mode 100644
index 000000000..198ebfb7a
--- /dev/null
+++ b/lesson_21/README.md
@@ -0,0 +1,12 @@
+# Lesson 21: Computer Languages ([Slides](https://code-differently.github.io/code-differently-25-q1/slides/#/lesson_21))
+
+## Pre-work
+
+Please review the following resources before lecture:
+
+* [Programming Paradigms Explained (Video)](https://www.youtube.com/watch?v=H5uA6p_pK-Y)
+* [Ditch your Favorite Programming Paradigm (Video)](https://www.youtube.com/watch?v=UOkOA6W-vwc)
+
+## Homework
+
+- TODO(anthonydmays): Figure this out
\ No newline at end of file