diff --git a/mongodb-optimization-tips/.gitignore b/mongodb-optimization-tips/.gitignore
new file mode 100644
index 0000000..549e00a
--- /dev/null
+++ b/mongodb-optimization-tips/.gitignore
@@ -0,0 +1,33 @@
+HELP.md
+target/
+!.mvn/wrapper/maven-wrapper.jar
+!**/src/main/**/target/
+!**/src/test/**/target/
+
+### STS ###
+.apt_generated
+.classpath
+.factorypath
+.project
+.settings
+.springBeans
+.sts4-cache
+
+### IntelliJ IDEA ###
+.idea
+*.iws
+*.iml
+*.ipr
+
+### NetBeans ###
+/nbproject/private/
+/nbbuild/
+/dist/
+/nbdist/
+/.nb-gradle/
+build/
+!**/src/main/**/build/
+!**/src/test/**/build/
+
+### VS Code ###
+.vscode/
diff --git a/mongodb-optimization-tips/build.gradle b/mongodb-optimization-tips/build.gradle
new file mode 100644
index 0000000..ae1230d
--- /dev/null
+++ b/mongodb-optimization-tips/build.gradle
@@ -0,0 +1,34 @@
+plugins {
+    id 'java'
+    id 'org.springframework.boot' version '3.2.3'
+    id 'io.spring.dependency-management' version '1.1.4'
+}
+
+group = 'com.stacktips'
+version = '0.0.1-SNAPSHOT'
+
+java {
+    sourceCompatibility = '17'
+}
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    implementation 'org.springframework.boot:spring-boot-starter-data-mongodb'
+    implementation 'org.springframework.boot:spring-boot-starter-web'
+    implementation 'org.projectlombok:lombok'
+    annotationProcessor('org.projectlombok:lombok')
+
+    testImplementation 'org.springframework.boot:spring-boot-starter-test'
+    testImplementation 'org.springframework.boot:spring-boot-testcontainers'
+    testImplementation 'org.testcontainers:junit-jupiter'
+    testImplementation 'org.testcontainers:mongodb'
+    implementation 'com.opencsv:opencsv:5.7.1'
+
+}
+
+tasks.named('test') {
+    useJUnitPlatform()
+}
diff --git a/mongodb-optimization-tips/gradle/wrapper/gradle-wrapper.jar b/mongodb-optimization-tips/gradle/wrapper/gradle-wrapper.jar
new file mode 100644
index 0000000..d64cd49
Binary files /dev/null and b/mongodb-optimization-tips/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/mongodb-optimization-tips/gradle/wrapper/gradle-wrapper.properties b/mongodb-optimization-tips/gradle/wrapper/gradle-wrapper.properties
new file mode 100644
index 0000000..1af9e09
--- /dev/null
+++ b/mongodb-optimization-tips/gradle/wrapper/gradle-wrapper.properties
@@ -0,0 +1,7 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.5-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
diff --git a/mongodb-optimization-tips/gradlew b/mongodb-optimization-tips/gradlew
new file mode 100755
index 0000000..1aa94a4
--- /dev/null
+++ b/mongodb-optimization-tips/gradlew
@@ -0,0 +1,249 @@
+#!/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.
+#
+
+##############################################################################
+#
+#   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/subprojects/plugins/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 "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD=maximum
+
+warn () {
+    echo "$*"
+} >&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/mongodb-optimization-tips/gradlew.bat b/mongodb-optimization-tips/gradlew.bat
new file mode 100644
index 0000000..93e3f59
--- /dev/null
+++ b/mongodb-optimization-tips/gradlew.bat
@@ -0,0 +1,92 @@
+@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
+
+@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.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto execute
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+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/mongodb-optimization-tips/readme.md b/mongodb-optimization-tips/readme.md
new file mode 100644
index 0000000..deafcbb
--- /dev/null
+++ b/mongodb-optimization-tips/readme.md
@@ -0,0 +1,22 @@
+# Testing Spring Boot Repository Using MongoDB Testcontainers
+
+Testcontainers are lightweight, throwaway container instances, used for common test cases like testing against a database, ActiveMQ or anything else that can run in a Docker container.
+
+Testcontainers allows you to run your tests against a real instance of your application's dependencies, such as a real database, rather than against a mock or an in-memory database. We can configure the Testcontainers to closely mimic the production environment by using the specific versions of your dependencies and pre-loading with test data.
+
+It spins up a new container instance for each test, hence every test is completely isolated from each other.
+
+For running tests using the Testcontainers, we need to have the docker up and running, no other dependencies are required.
+
+Read [the full article here](https://stacktips.com/articles/testing-spring-boot-repository-using-mongodb-testcontainers)
+
+### Related topics:
+
+* [#spring-boot](https://stacktips.com/topics/spring-boot)
+* [#android](https://stacktips.com/topics/android)
+* [#java](https://stacktips.com/topics/java)
+* [#python](https://stacktips.com/topics/python)
+* [#spring](https://stacktips.com/topics/spring)
+* [#design-pattern](https://stacktips.com/topics/design-pattern)
+* [#git](https://stacktips.com/topics/git)
+* [#maven](https://stacktips.com/topics/maven)
diff --git a/mongodb-optimization-tips/settings.gradle b/mongodb-optimization-tips/settings.gradle
new file mode 100644
index 0000000..5d549ef
--- /dev/null
+++ b/mongodb-optimization-tips/settings.gradle
@@ -0,0 +1 @@
+rootProject.name = 'mongodb-optimization-tips'
diff --git a/mongodb-optimization-tips/src/main/java/com/stacktips/movies/MoviesApiApplication.java b/mongodb-optimization-tips/src/main/java/com/stacktips/movies/MoviesApiApplication.java
new file mode 100644
index 0000000..92a624b
--- /dev/null
+++ b/mongodb-optimization-tips/src/main/java/com/stacktips/movies/MoviesApiApplication.java
@@ -0,0 +1,14 @@
+package com.stacktips.movies;
+
+import lombok.RequiredArgsConstructor;
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+@RequiredArgsConstructor
+public class MoviesApiApplication {
+
+    public static void main(String[] args) {
+        SpringApplication.run(MoviesApiApplication.class, args);
+    }
+}
diff --git a/mongodb-optimization-tips/src/main/java/com/stacktips/movies/config/MongoConfiguration.java b/mongodb-optimization-tips/src/main/java/com/stacktips/movies/config/MongoConfiguration.java
new file mode 100644
index 0000000..ba92910
--- /dev/null
+++ b/mongodb-optimization-tips/src/main/java/com/stacktips/movies/config/MongoConfiguration.java
@@ -0,0 +1,31 @@
+package com.stacktips.movies.config;
+
+import com.mongodb.ReadPreference;
+import com.mongodb.WriteConcern;
+import org.springframework.boot.autoconfigure.mongo.MongoClientSettingsBuilderCustomizer;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.data.mongodb.core.WriteConcernResolver;
+
+@Configuration
+public class MongoConfiguration {
+
+    @Bean
+    public WriteConcernResolver writeConcernResolver() {
+        return action -> {
+            String entityName = action.getEntityType().getSimpleName();
+            if (entityName.contains("Product")) {
+                return WriteConcern.ACKNOWLEDGED;
+            } else if (entityName.contains("Metadata")) {
+                return WriteConcern.JOURNALED;
+            }
+            return action.getDefaultWriteConcern();
+
+        };
+    }
+
+    @Bean
+    public MongoClientSettingsBuilderCustomizer monoClientCustomizer() {
+        return builder -> builder.readPreference(ReadPreference.nearest());
+    }
+}
\ No newline at end of file
diff --git a/mongodb-optimization-tips/src/main/java/com/stacktips/movies/dto/TotalSales.java b/mongodb-optimization-tips/src/main/java/com/stacktips/movies/dto/TotalSales.java
new file mode 100644
index 0000000..67b5985
--- /dev/null
+++ b/mongodb-optimization-tips/src/main/java/com/stacktips/movies/dto/TotalSales.java
@@ -0,0 +1,13 @@
+package com.stacktips.movies.dto;
+
+import lombok.Getter;
+import lombok.Setter;
+import lombok.ToString;
+
+@Getter
+@Setter
+@ToString
+public class TotalSales {
+    private String productName;
+    private double totalSales;
+}
diff --git a/mongodb-optimization-tips/src/main/java/com/stacktips/movies/models/LogEntry.java b/mongodb-optimization-tips/src/main/java/com/stacktips/movies/models/LogEntry.java
new file mode 100644
index 0000000..d63ead6
--- /dev/null
+++ b/mongodb-optimization-tips/src/main/java/com/stacktips/movies/models/LogEntry.java
@@ -0,0 +1,17 @@
+package com.stacktips.movies.models;
+
+import lombok.*;
+import org.springframework.data.annotation.Id;
+import org.springframework.data.mongodb.core.mapping.Document;
+
+@Getter
+@Setter
+@AllArgsConstructor
+@RequiredArgsConstructor
+@Document(collection = "logs")
+public class LogEntry {
+
+    @Id
+    private String id;
+    private final String log;
+}
diff --git a/mongodb-optimization-tips/src/main/java/com/stacktips/movies/models/Price.java b/mongodb-optimization-tips/src/main/java/com/stacktips/movies/models/Price.java
new file mode 100644
index 0000000..f121b93
--- /dev/null
+++ b/mongodb-optimization-tips/src/main/java/com/stacktips/movies/models/Price.java
@@ -0,0 +1,19 @@
+package com.stacktips.movies.models;
+
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+import lombok.Setter;
+import org.springframework.data.annotation.Id;
+import org.springframework.data.mongodb.core.mapping.Document;
+
+@Getter
+@Setter
+@NoArgsConstructor
+@AllArgsConstructor
+@Document(collection = "Price")
+public class Price {
+    @Id
+    private String id;
+    private double price;
+}
diff --git a/mongodb-optimization-tips/src/main/java/com/stacktips/movies/models/Product.java b/mongodb-optimization-tips/src/main/java/com/stacktips/movies/models/Product.java
new file mode 100644
index 0000000..324f40e
--- /dev/null
+++ b/mongodb-optimization-tips/src/main/java/com/stacktips/movies/models/Product.java
@@ -0,0 +1,20 @@
+package com.stacktips.movies.models;
+
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+import lombok.Setter;
+import org.springframework.data.annotation.Id;
+import org.springframework.data.mongodb.core.mapping.Document;
+
+@Getter
+@Setter
+@AllArgsConstructor
+@NoArgsConstructor
+@Document(collection = "Product")
+public class Product {
+    @Id
+    private String id;
+    private String name;
+    private String brand;
+}
diff --git a/mongodb-optimization-tips/src/main/java/com/stacktips/movies/models/Sales.java b/mongodb-optimization-tips/src/main/java/com/stacktips/movies/models/Sales.java
new file mode 100644
index 0000000..2b31808
--- /dev/null
+++ b/mongodb-optimization-tips/src/main/java/com/stacktips/movies/models/Sales.java
@@ -0,0 +1,24 @@
+package com.stacktips.movies.models;
+
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+import lombok.Setter;
+import org.bson.types.ObjectId;
+import org.springframework.data.annotation.Id;
+import org.springframework.data.mongodb.core.mapping.Document;
+
+import java.util.Date;
+
+@Getter
+@Setter
+@AllArgsConstructor
+@NoArgsConstructor
+@Document(collection = "Sales")
+public class Sales {
+    @Id
+    private String id;
+    private String productId;
+    private int quantity;
+    private Date date;
+}
diff --git a/mongodb-optimization-tips/src/main/java/com/stacktips/movies/repository/ProductRepository.java b/mongodb-optimization-tips/src/main/java/com/stacktips/movies/repository/ProductRepository.java
new file mode 100644
index 0000000..6e1b2fc
--- /dev/null
+++ b/mongodb-optimization-tips/src/main/java/com/stacktips/movies/repository/ProductRepository.java
@@ -0,0 +1,26 @@
+package com.stacktips.movies.repository;
+
+import com.stacktips.movies.models.Product;
+import org.springframework.data.domain.PageRequest;
+import org.springframework.data.domain.Pageable;
+import org.springframework.data.mongodb.core.MongoTemplate;
+import org.springframework.data.mongodb.core.query.Query;
+import org.springframework.stereotype.Repository;
+
+import java.util.List;
+
+@Repository
+public class ProductRepository {
+
+    private final MongoTemplate mongoTemplate;
+
+    public ProductRepository(MongoTemplate mongoTemplate) {
+        this.mongoTemplate = mongoTemplate;
+    }
+
+    public List<Product> getProducts(int page, int size) {
+        Pageable pageable = PageRequest.of(page, size);
+        Query query = new Query().with(pageable);
+        return mongoTemplate.find(query, Product.class);
+    }
+}
diff --git a/mongodb-optimization-tips/src/main/java/com/stacktips/movies/repository/SalesRepository.java b/mongodb-optimization-tips/src/main/java/com/stacktips/movies/repository/SalesRepository.java
new file mode 100644
index 0000000..18246af
--- /dev/null
+++ b/mongodb-optimization-tips/src/main/java/com/stacktips/movies/repository/SalesRepository.java
@@ -0,0 +1,64 @@
+package com.stacktips.movies.repository;
+
+import com.stacktips.movies.dto.TotalSales;
+import lombok.RequiredArgsConstructor;
+import org.springframework.data.mongodb.core.MongoTemplate;
+import org.springframework.data.mongodb.core.aggregation.*;
+import org.springframework.data.mongodb.core.query.Criteria;
+import org.springframework.stereotype.Repository;
+
+import java.util.Calendar;
+import java.util.Date;
+import java.util.List;
+
+@Repository
+@RequiredArgsConstructor
+public class SalesRepository {
+
+    private final MongoTemplate mongoTemplate;
+
+    public List<TotalSales> calculateLastMonthSales() {
+        MatchOperation matchStage = Aggregation.match(Criteria.where("date")
+                .gte(getLastMonthStartDate())
+                .lte(new Date()));
+
+        LookupOperation lookupProduct = Aggregation.lookup(
+                "Product", "productId", "_id", "product");
+        LookupOperation lookupPrice = Aggregation.lookup(
+                "Price", "productId", "_id", "price");
+        UnwindOperation unwindProduct = Aggregation.unwind("product");
+        UnwindOperation unwindPrice = Aggregation.unwind("price");
+
+        GroupOperation groupStage = Aggregation.group("product.name")
+                .sum(ArithmeticOperators.Multiply.valueOf("quantity")
+                        .multiplyBy("price.price"))
+                .as("totalSales");
+
+        ProjectionOperation projectStage = Aggregation.project()
+                .andExpression("_id").as("productName")
+                .andExpression("totalSales").as("totalSales")
+                .andExclude("_id");
+
+        Aggregation aggregation = Aggregation.newAggregation(matchStage,
+                lookupProduct,
+                unwindProduct,
+                lookupPrice,
+                unwindPrice,
+                groupStage,
+                projectStage);
+        AggregationResults<TotalSales> results = mongoTemplate.aggregate(
+                aggregation, "Sales", TotalSales.class);
+        return results.getMappedResults();
+    }
+
+    private Date getLastMonthStartDate() {
+        Calendar calendar = Calendar.getInstance();
+        calendar.add(Calendar.MONTH, -1);
+        calendar.set(Calendar.DAY_OF_MONTH, 1);
+        calendar.set(Calendar.HOUR_OF_DAY, 0);
+        calendar.set(Calendar.MINUTE, 0);
+        calendar.set(Calendar.SECOND, 0);
+        calendar.set(Calendar.MILLISECOND, 0);
+        return calendar.getTime();
+    }
+}
diff --git a/mongodb-optimization-tips/src/main/java/com/stacktips/movies/services/ApplicationLogger.java b/mongodb-optimization-tips/src/main/java/com/stacktips/movies/services/ApplicationLogger.java
new file mode 100644
index 0000000..34cb1a3
--- /dev/null
+++ b/mongodb-optimization-tips/src/main/java/com/stacktips/movies/services/ApplicationLogger.java
@@ -0,0 +1,40 @@
+package com.stacktips.movies.services;
+
+import com.stacktips.movies.models.LogEntry;
+import jakarta.annotation.PostConstruct;
+import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.boot.CommandLineRunner;
+import org.springframework.data.mongodb.core.CollectionOptions;
+import org.springframework.data.mongodb.core.MongoTemplate;
+import org.springframework.data.mongodb.core.query.Query;
+import org.springframework.stereotype.Component;
+
+@Slf4j
+@Component
+@RequiredArgsConstructor
+public class ApplicationLogger implements CommandLineRunner {
+
+    private final MongoTemplate mongoTemplate;
+
+    private static final long MAX_SIZE = 5 * 1024 * 1024;
+    private static final long MAX_DOCUMENTS = 100;
+
+    @PostConstruct
+    public void init() {
+        if (!mongoTemplate.collectionExists(LogEntry.class)) {
+            mongoTemplate.createCollection(LogEntry.class,
+                    CollectionOptions.empty().capped()
+                            .size(MAX_SIZE)
+                            .maxDocuments(MAX_DOCUMENTS));
+        }
+    }
+
+    @Override
+    public void run(String... args) throws Exception {
+        for (int i = 1; i <= 1500; i++) {
+            mongoTemplate.save(new LogEntry("Log entry " + i));
+        }
+        log.info("Size: {0}", mongoTemplate.count(new Query(), LogEntry.class));
+    }
+}
\ No newline at end of file
diff --git a/mongodb-optimization-tips/src/main/java/com/stacktips/movies/services/DataLoader.java b/mongodb-optimization-tips/src/main/java/com/stacktips/movies/services/DataLoader.java
new file mode 100644
index 0000000..8c67f8d
--- /dev/null
+++ b/mongodb-optimization-tips/src/main/java/com/stacktips/movies/services/DataLoader.java
@@ -0,0 +1,41 @@
+package com.stacktips.movies.services;
+
+import com.opencsv.bean.CsvToBeanBuilder;
+import com.stacktips.movies.models.Product;
+import lombok.RequiredArgsConstructor;
+import org.springframework.boot.CommandLineRunner;
+import org.springframework.data.mongodb.core.BulkOperations;
+import org.springframework.data.mongodb.core.MongoTemplate;
+import org.springframework.stereotype.Component;
+
+import java.io.FileReader;
+import java.io.IOException;
+import java.io.Reader;
+import java.util.List;
+
+@Component
+@RequiredArgsConstructor
+public class DataLoader implements CommandLineRunner {
+
+    private static final String FILE_PATH = "src/main/resources/products.csv";
+
+    private final MongoTemplate mongoTemplate;
+
+    @Override
+    public void run(String... args) throws Exception {
+        List<Product> products = parseCsv(FILE_PATH, Product.class)
+                .stream()
+                .map(row -> new Product(row.getId(), row.getName(), row.getBrand()))
+                .toList();
+
+        mongoTemplate.bulkOps(BulkOperations.BulkMode.ORDERED, Product.class)
+                .insert(products)
+                .execute();
+    }
+
+    public static <T> List<T> parseCsv(String filePath, Class<T> type) throws IOException {
+        try (Reader reader = new FileReader(filePath)) {
+            return new CsvToBeanBuilder<T>(reader).withType(type).build().parse();
+        }
+    }
+}
diff --git a/mongodb-optimization-tips/src/main/resources/application.yaml b/mongodb-optimization-tips/src/main/resources/application.yaml
new file mode 100644
index 0000000..46528fa
--- /dev/null
+++ b/mongodb-optimization-tips/src/main/resources/application.yaml
@@ -0,0 +1,15 @@
+spring:
+  data:
+    mongodb:
+      uri: mongodb://localhost:27017/mongodb_optimization_tips
+      authentication-database: admin
+
+logging:
+  level:
+    org:
+      springframework:
+        data:
+          mongodb:
+            core:
+              MongoTemplate: debug
+    root: warn
\ No newline at end of file
diff --git a/mongodb-optimization-tips/src/main/resources/products.csv b/mongodb-optimization-tips/src/main/resources/products.csv
new file mode 100644
index 0000000..9a267c5
--- /dev/null
+++ b/mongodb-optimization-tips/src/main/resources/products.csv
@@ -0,0 +1,101 @@
+id,name,brand
+productId1,Product 0,Brand A
+productId2,Product 1,Brand C
+productId3,Product 2,Brand E
+productId4,Product 3,Brand C
+productId5,Product 4,Brand E
+productId6,Product 5,Brand D
+productId7,Product 6,Brand A
+productId8,Product 7,Brand B
+productId9,Product 8,Brand A
+productId10,Product 9,Brand A
+productId11,Product 10,Brand A
+productId12,Product 11,Brand E
+productId13,Product 12,Brand B
+productId14,Product 13,Brand E
+productId15,Product 14,Brand B
+productId16,Product 15,Brand E
+productId17,Product 16,Brand E
+productId18,Product 17,Brand B
+productId19,Product 18,Brand A
+productId20,Product 19,Brand E
+productId21,Product 20,Brand D
+productId22,Product 21,Brand E
+productId23,Product 22,Brand B
+productId24,Product 23,Brand A
+productId25,Product 24,Brand D
+productId26,Product 25,Brand C
+productId27,Product 26,Brand E
+productId28,Product 27,Brand E
+productId29,Product 28,Brand B
+productId30,Product 29,Brand A
+productId31,Product 30,Brand E
+productId32,Product 31,Brand C
+productId33,Product 32,Brand D
+productId34,Product 33,Brand B
+productId35,Product 34,Brand E
+productId36,Product 35,Brand E
+productId37,Product 36,Brand B
+productId38,Product 37,Brand B
+productId39,Product 38,Brand D
+productId40,Product 39,Brand D
+productId41,Product 40,Brand D
+productId42,Product 41,Brand A
+productId43,Product 42,Brand B
+productId44,Product 43,Brand C
+productId45,Product 44,Brand D
+productId46,Product 45,Brand D
+productId47,Product 46,Brand E
+productId48,Product 47,Brand D
+productId49,Product 48,Brand D
+productId50,Product 49,Brand D
+productId51,Product 50,Brand D
+productId52,Product 51,Brand B
+productId53,Product 52,Brand C
+productId54,Product 53,Brand B
+productId55,Product 54,Brand A
+productId56,Product 55,Brand C
+productId57,Product 56,Brand B
+productId58,Product 57,Brand C
+productId59,Product 58,Brand C
+productId60,Product 59,Brand E
+productId61,Product 60,Brand D
+productId62,Product 61,Brand D
+productId63,Product 62,Brand E
+productId64,Product 63,Brand E
+productId65,Product 64,Brand D
+productId66,Product 65,Brand E
+productId67,Product 66,Brand C
+productId68,Product 67,Brand B
+productId69,Product 68,Brand D
+productId70,Product 69,Brand D
+productId71,Product 70,Brand C
+productId72,Product 71,Brand C
+productId73,Product 72,Brand A
+productId74,Product 73,Brand D
+productId75,Product 74,Brand B
+productId76,Product 75,Brand C
+productId77,Product 76,Brand C
+productId78,Product 77,Brand C
+productId79,Product 78,Brand A
+productId80,Product 79,Brand A
+productId81,Product 80,Brand B
+productId82,Product 81,Brand C
+productId83,Product 82,Brand E
+productId84,Product 83,Brand D
+productId85,Product 84,Brand B
+productId86,Product 85,Brand D
+productId87,Product 86,Brand C
+productId88,Product 87,Brand D
+productId89,Product 88,Brand D
+productId90,Product 89,Brand D
+productId91,Product 90,Brand D
+productId92,Product 91,Brand B
+productId93,Product 92,Brand C
+productId94,Product 93,Brand C
+productId95,Product 94,Brand D
+productId96,Product 95,Brand E
+productId97,Product 96,Brand A
+productId98,Product 97,Brand B
+productId99,Product 98,Brand D
+productId100,Product 99,Brand B
diff --git a/mongodb-optimization-tips/src/test/java/com/stacktips/movies/repository/SalesRepositoryTest.java b/mongodb-optimization-tips/src/test/java/com/stacktips/movies/repository/SalesRepositoryTest.java
new file mode 100644
index 0000000..ae16cc7
--- /dev/null
+++ b/mongodb-optimization-tips/src/test/java/com/stacktips/movies/repository/SalesRepositoryTest.java
@@ -0,0 +1,113 @@
+package com.stacktips.movies.repository;
+
+import com.stacktips.movies.dto.TotalSales;
+import com.stacktips.movies.models.Price;
+import com.stacktips.movies.models.Product;
+import com.stacktips.movies.models.Sales;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.autoconfigure.data.mongo.DataMongoTest;
+import org.springframework.context.annotation.ComponentScan;
+import org.springframework.data.mongodb.core.MongoTemplate;
+import org.springframework.stereotype.Repository;
+import org.springframework.test.context.DynamicPropertyRegistry;
+import org.springframework.test.context.DynamicPropertySource;
+import org.testcontainers.containers.MongoDBContainer;
+import org.testcontainers.junit.jupiter.Container;
+import org.testcontainers.junit.jupiter.Testcontainers;
+
+import java.util.Calendar;
+import java.util.Date;
+import java.util.List;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.*;
+
+@Testcontainers
+@DataMongoTest(includeFilters = @ComponentScan.Filter(Repository.class))
+class SalesRepositoryTest {
+
+    @Autowired
+    SalesRepository repository;
+
+    @Autowired
+    MongoTemplate mongoTemplate;
+
+    @Container
+    static final MongoDBContainer mongoDbContainer = new MongoDBContainer("mongo:latest")
+            .withExposedPorts(27017);
+
+    @DynamicPropertySource
+    static void setProperties(DynamicPropertyRegistry registry) {
+        registry.add("spring.data.mongodb.host", mongoDbContainer::getHost);
+        registry.add("spring.data.mongodb.port", mongoDbContainer::getFirstMappedPort);
+        registry.add("spring.data.mongodb.username", () -> "test_user");
+        registry.add("spring.data.mongodb.password", () -> "test_password");
+        registry.add("spring.data.mongodb.database", () -> "movies_db");
+        registry.add("spring.data.mongodb.uri", mongoDbContainer::getReplicaSetUrl);
+    }
+
+    static {
+        mongoDbContainer.start();
+    }
+
+    @BeforeEach
+    public void setUp() {
+        mongoTemplate.dropCollection("Product");
+        mongoTemplate.dropCollection("Price");
+        mongoTemplate.dropCollection("Sales");
+        List<Product> products = List.of(
+                new Product("productId1", "Product A", "Brand A"),
+                new Product("productId2", "Product B", "Brand B"),
+                new Product("productId3", "Product B", "Brand C")
+        );
+        List<Price> prices = List.of(
+                new Price("productId1", 100),
+                new Price("productId2", 200),
+                new Price("productId3", 150)
+        );
+        List<Sales> sales = List.of(
+                new Sales("saleId1", "productId1", 3, getSaleDate(1)),
+                new Sales("saleId2", "productId1", 3, getSaleDate(3)),
+                new Sales("saleId3", "productId1", 5, getSaleDate(1)),
+                new Sales("saleId4", "productId2", 3, getSaleDate(1))
+        );
+
+        mongoTemplate.insertAll(products);
+        mongoTemplate.insertAll(prices);
+        mongoTemplate.insertAll(sales);
+    }
+
+    @Test
+    void testCalculateLastMonthSales() {
+        List<TotalSales> totalSalesList = repository.calculateLastMonthSales();
+        System.out.println(totalSalesList);
+
+        assertThat(totalSalesList, is(notNullValue()));
+        assertThat(totalSalesList.size(), comparesEqualTo(2));
+
+        TotalSales productASales = totalSalesList.stream()
+                .filter(totalSales -> "Product A".equals(totalSales.getProductName()))
+                .findFirst()
+                .orElse(null);
+
+        TotalSales productBSales = totalSalesList.stream()
+                .filter(totalSales -> "Product B".equals(totalSales.getProductName()))
+                .findFirst()
+                .orElse(null);
+
+        assertThat(productASales, is(notNullValue()));
+        assertThat(productBSales, is(notNullValue()));
+        assertThat(productASales.getTotalSales(), is(800.0));
+
+        assertThat(productBSales, is(notNullValue()));
+        assertThat(productBSales.getTotalSales(), is(600.0));
+    }
+
+    Date getSaleDate(int monthsToGoBack) {
+        Calendar calendar = Calendar.getInstance();
+        calendar.add(Calendar.MONTH, -monthsToGoBack);
+        return calendar.getTime();
+    }
+}
\ No newline at end of file
diff --git a/spring-boot-feature-toggle/.gitignore b/spring-boot-feature-toggle/.gitignore
new file mode 100644
index 0000000..c2065bc
--- /dev/null
+++ b/spring-boot-feature-toggle/.gitignore
@@ -0,0 +1,37 @@
+HELP.md
+.gradle
+build/
+!gradle/wrapper/gradle-wrapper.jar
+!**/src/main/**/build/
+!**/src/test/**/build/
+
+### STS ###
+.apt_generated
+.classpath
+.factorypath
+.project
+.settings
+.springBeans
+.sts4-cache
+bin/
+!**/src/main/**/bin/
+!**/src/test/**/bin/
+
+### IntelliJ IDEA ###
+.idea
+*.iws
+*.iml
+*.ipr
+out/
+!**/src/main/**/out/
+!**/src/test/**/out/
+
+### NetBeans ###
+/nbproject/private/
+/nbbuild/
+/dist/
+/nbdist/
+/.nb-gradle/
+
+### VS Code ###
+.vscode/
diff --git a/spring-boot-feature-toggle/build.gradle b/spring-boot-feature-toggle/build.gradle
new file mode 100644
index 0000000..a9fe461
--- /dev/null
+++ b/spring-boot-feature-toggle/build.gradle
@@ -0,0 +1,28 @@
+plugins {
+	id 'java'
+	id 'org.springframework.boot' version '3.3.0'
+	id 'io.spring.dependency-management' version '1.1.5'
+}
+
+group = 'com.stacktips.app'
+version = '0.0.1-SNAPSHOT'
+
+java {
+	toolchain {
+		languageVersion = JavaLanguageVersion.of(21)
+	}
+}
+
+repositories {
+	mavenCentral()
+}
+
+dependencies {
+	implementation 'org.springframework.boot:spring-boot-starter-web'
+	testImplementation 'org.springframework.boot:spring-boot-starter-test'
+	testRuntimeOnly 'org.junit.platform:junit-platform-launcher'
+}
+
+tasks.named('test') {
+	useJUnitPlatform()
+}
diff --git a/spring-boot-feature-toggle/gradle/wrapper/gradle-wrapper.jar b/spring-boot-feature-toggle/gradle/wrapper/gradle-wrapper.jar
new file mode 100644
index 0000000..e644113
Binary files /dev/null and b/spring-boot-feature-toggle/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/spring-boot-feature-toggle/gradle/wrapper/gradle-wrapper.properties b/spring-boot-feature-toggle/gradle/wrapper/gradle-wrapper.properties
new file mode 100644
index 0000000..a441313
--- /dev/null
+++ b/spring-boot-feature-toggle/gradle/wrapper/gradle-wrapper.properties
@@ -0,0 +1,7 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.8-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
diff --git a/spring-boot-feature-toggle/gradlew b/spring-boot-feature-toggle/gradlew
new file mode 100755
index 0000000..b740cf1
--- /dev/null
+++ b/spring-boot-feature-toggle/gradlew
@@ -0,0 +1,249 @@
+#!/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.
+#
+
+##############################################################################
+#
+#   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 "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD=maximum
+
+warn () {
+    echo "$*"
+} >&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/spring-boot-feature-toggle/gradlew.bat b/spring-boot-feature-toggle/gradlew.bat
new file mode 100644
index 0000000..7101f8e
--- /dev/null
+++ b/spring-boot-feature-toggle/gradlew.bat
@@ -0,0 +1,92 @@
+@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
+
+@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/spring-boot-feature-toggle/settings.gradle b/spring-boot-feature-toggle/settings.gradle
new file mode 100644
index 0000000..d8c35df
--- /dev/null
+++ b/spring-boot-feature-toggle/settings.gradle
@@ -0,0 +1 @@
+rootProject.name = 'spring-boot-feature-toggle'
diff --git a/spring-boot-feature-toggle/src/main/java/com/stacktips/app/MyApplication.java b/spring-boot-feature-toggle/src/main/java/com/stacktips/app/MyApplication.java
new file mode 100644
index 0000000..69d8a40
--- /dev/null
+++ b/spring-boot-feature-toggle/src/main/java/com/stacktips/app/MyApplication.java
@@ -0,0 +1,13 @@
+package com.stacktips.app;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class MyApplication {
+
+	public static void main(String[] args) {
+		SpringApplication.run(MyApplication.class, args);
+	}
+
+}
diff --git a/spring-boot-feature-toggle/src/main/resources/application.properties b/spring-boot-feature-toggle/src/main/resources/application.properties
new file mode 100644
index 0000000..ed79ec5
--- /dev/null
+++ b/spring-boot-feature-toggle/src/main/resources/application.properties
@@ -0,0 +1 @@
+spring.application.name=spring-boot-feature-toggle
diff --git a/spring-boot-feature-toggle/src/test/java/com/stacktips/app/MyApplicationTests.java b/spring-boot-feature-toggle/src/test/java/com/stacktips/app/MyApplicationTests.java
new file mode 100644
index 0000000..7782f23
--- /dev/null
+++ b/spring-boot-feature-toggle/src/test/java/com/stacktips/app/MyApplicationTests.java
@@ -0,0 +1,13 @@
+package com.stacktips.app;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.boot.test.context.SpringBootTest;
+
+@SpringBootTest
+class MyApplicationTests {
+
+	@Test
+	void contextLoads() {
+	}
+
+}
diff --git a/spring-dependency-injection/spring-dependency-injection/build2.gradle b/spring-dependency-injection/spring-dependency-injection/build2.gradle
new file mode 100644
index 0000000..d02cf27
--- /dev/null
+++ b/spring-dependency-injection/spring-dependency-injection/build2.gradle
@@ -0,0 +1,46 @@
+plugins {
+    id 'java'
+    id 'org.springframework.boot' version '3.2.5'
+    id 'io.spring.dependency-management' version '1.1.4'
+}
+
+group = 'com.stacktps.app'
+version = '0.0.1-SNAPSHOT'
+
+java {
+    sourceCompatibility = '21'
+}
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    implementation 'org.springframework.boot:spring-boot-starter-data-jpa'
+    implementation 'org.springframework.boot:spring-boot-starter-web'
+    testImplementation 'org.springframework.boot:spring-boot-starter-test'
+    testRuntimeOnly 'org.junit.platform:junit-platform-launcher'
+}
+
+tasks.named('test') {
+    useJUnitPlatform()
+}
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
diff --git a/spring-dependency-injection/spring-dependency-injection/pom.xml b/spring-dependency-injection/spring-dependency-injection/pom.xml
new file mode 100644
index 0000000..aac245a
--- /dev/null
+++ b/spring-dependency-injection/spring-dependency-injection/pom.xml
@@ -0,0 +1,44 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0
+                    https://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <parent>
+        <groupId>org.springframework.boot</groupId>
+        <artifactId>spring-boot-starter-parent</artifactId>
+        <version>3.2.5</version>
+        <relativePath/> <!-- lookup parent from repository -->
+    </parent>
+    <groupId>com.stacktps.app</groupId>
+    <artifactId>movies-api</artifactId>
+    <version>0.0.1-SNAPSHOT</version>
+    <name>movies-api</name>
+    <description>Demo project for Spring Boot</description>
+    <properties>
+        <java.version>21</java.version>
+    </properties>
+
+
+    <dependencies>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-data-jpa</artifactId>
+        </dependency>
+    </dependencies>
+
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.springframework.boot</groupId>
+                <artifactId>spring-boot-maven-plugin</artifactId>
+            </plugin>
+        </plugins>
+    </build>
+</project>
+
+
+
+
+