diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000000000000000000000000000000000000..ad8a47ed440511696e71d483fd71c146c459c572
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,15 @@
+#Gradle
+.gradle/
+build/
+
+# Eclipse
+.classpath
+.project
+.settings/
+bin/
+
+# IntelliJ IDEA
+.idea/
+*.iml
+*.iws
+*.ipr
diff --git a/barcode-tasking-sample/build.gradle b/barcode-tasking-sample/build.gradle
new file mode 100644
index 0000000000000000000000000000000000000000..3cae2d720fb5d1f4383313e27f1395b2b3a30385
--- /dev/null
+++ b/barcode-tasking-sample/build.gradle
@@ -0,0 +1,19 @@
+plugins {
+    id 'java'
+}
+
+group 'org.example'
+version '1.0-SNAPSHOT'
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    testImplementation 'org.junit.jupiter:junit-jupiter-api:5.8.1'
+    testRuntimeOnly 'org.junit.jupiter:junit-jupiter-engine:5.8.1'
+}
+
+test {
+    useJUnitPlatform()
+}
\ No newline at end of file
diff --git a/barcode-tasking-sample/gradle/wrapper/gradle-wrapper.jar b/barcode-tasking-sample/gradle/wrapper/gradle-wrapper.jar
new file mode 100644
index 0000000000000000000000000000000000000000..41d9927a4d4fb3f96a785543079b8df6723c946b
Binary files /dev/null and b/barcode-tasking-sample/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/barcode-tasking-sample/gradle/wrapper/gradle-wrapper.properties b/barcode-tasking-sample/gradle/wrapper/gradle-wrapper.properties
new file mode 100644
index 0000000000000000000000000000000000000000..41dfb87909a877d96c3af4adccce4c7a301b55a2
--- /dev/null
+++ b/barcode-tasking-sample/gradle/wrapper/gradle-wrapper.properties
@@ -0,0 +1,5 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-7.4-bin.zip
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
diff --git a/barcode-tasking-sample/gradlew b/barcode-tasking-sample/gradlew
new file mode 100755
index 0000000000000000000000000000000000000000..1b6c787337ffb79f0e3cf8b1e9f00f680a959de1
--- /dev/null
+++ b/barcode-tasking-sample/gradlew
@@ -0,0 +1,234 @@
+#!/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/master/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
+
+APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
+
+APP_NAME="Gradle"
+APP_BASE_NAME=${0##*/}
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD=maximum
+
+warn () {
+    echo "$*"
+} >&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: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD=java
+    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+
+# Increase the maximum file descriptors if we can.
+if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
+    case $MAX_FD in #(
+      max*)
+        MAX_FD=$( ulimit -H -n ) ||
+            warn "Could not query maximum file descriptor limit"
+    esac
+    case $MAX_FD in  #(
+      '' | soft) :;; #(
+      *)
+        ulimit -n "$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
+
+# Collect all arguments for the java command;
+#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
+#     shell script including quotes and variable substitutions, so put them in
+#     double quotes to make sure that they get re-expanded; and
+#   * put everything else in single quotes, so that it's not re-expanded.
+
+set -- \
+        "-Dorg.gradle.appname=$APP_BASE_NAME" \
+        -classpath "$CLASSPATH" \
+        org.gradle.wrapper.GradleWrapperMain \
+        "$@"
+
+# 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/barcode-tasking-sample/gradlew.bat b/barcode-tasking-sample/gradlew.bat
new file mode 100644
index 0000000000000000000000000000000000000000..ac1b06f93825db68fb0c0b5150917f340eaa5d02
--- /dev/null
+++ b/barcode-tasking-sample/gradlew.bat
@@ -0,0 +1,89 @@
+@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=.
+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%" == "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%"=="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!
+if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
+exit /b 1
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega
diff --git a/barcode-tasking-sample/settings.gradle b/barcode-tasking-sample/settings.gradle
new file mode 100644
index 0000000000000000000000000000000000000000..c164dd4e57250e44f6ef6ab2d069a916ce678d10
--- /dev/null
+++ b/barcode-tasking-sample/settings.gradle
@@ -0,0 +1,2 @@
+rootProject.name = 'barcode-tasking-sample'
+
diff --git a/barcode-tasking-sample/src/main/java/org/example/Barcode.java b/barcode-tasking-sample/src/main/java/org/example/Barcode.java
new file mode 100644
index 0000000000000000000000000000000000000000..911ee70791903bbd65a4e2d88e9c6aeba55791a5
--- /dev/null
+++ b/barcode-tasking-sample/src/main/java/org/example/Barcode.java
@@ -0,0 +1,26 @@
+package org.example;
+
+import java.util.Objects;
+
+public class Barcode {
+    public final String barcode;
+    public final int amount;
+    public Barcode(String barcode, int amount) {
+        this.barcode = barcode;
+        this.amount = amount;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) return true;
+        if (obj == null || getClass() != obj.getClass()) return false;
+
+        Barcode b = (Barcode) obj;
+        return Objects.equals(barcode, b.barcode) && amount == b.amount;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(barcode, amount);
+    }
+}
diff --git a/barcode-tasking-sample/src/main/java/org/example/BarcodesParser.java b/barcode-tasking-sample/src/main/java/org/example/BarcodesParser.java
new file mode 100644
index 0000000000000000000000000000000000000000..b92ac18edcfee7d8c362fd8d2facacd151ab7d7d
--- /dev/null
+++ b/barcode-tasking-sample/src/main/java/org/example/BarcodesParser.java
@@ -0,0 +1,34 @@
+package org.example;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class BarcodesParser {
+    public static List<Barcode> GroupBarcodes(List<Barcode> barcodesAndAmount) {
+        List<Barcode> groupedBarcodes = new ArrayList<>();
+        for (Barcode barcode : barcodesAndAmount) {
+            if (groupedBarcodes.contains(barcode)) {
+                continue;
+            }
+            groupedBarcodes.add(barcode);
+        }
+
+        return groupedBarcodes;
+    }
+
+    public static List<Barcode> ParseBarcodes(List<String> selectedBarcodes) {
+        List<Barcode> barcodesAndAmount = new ArrayList<>();
+        for (String barcodeAndAmount : selectedBarcodes) {
+            String[] res = barcodeAndAmount.split("-", 2);
+            if (res.length == 0) {
+                continue;
+            }
+
+            String barcode = res[0];
+            int amount = res.length == 2 ? Integer.parseInt(res[1]) : 1;
+            barcodesAndAmount.add(new Barcode(barcode, amount));
+        }
+
+        return barcodesAndAmount;
+    }
+}
diff --git a/barcode-tasking-sample/src/main/java/org/example/BarcodesValidation.java b/barcode-tasking-sample/src/main/java/org/example/BarcodesValidation.java
new file mode 100644
index 0000000000000000000000000000000000000000..bf1aaa828f6798b4a1a4e296d71fb2eff25a36c2
--- /dev/null
+++ b/barcode-tasking-sample/src/main/java/org/example/BarcodesValidation.java
@@ -0,0 +1,89 @@
+package org.example;
+
+import java.util.List;
+import java.util.Objects;
+
+public class BarcodesValidation {
+    public static String CreateErrorReceipt(ValidateErrorResult validationResult) {
+        if (validationResult.errorType == ValidateErrorType.INVALID_BARCODE) {
+            return "ERROR\n-------\nThe barcode cannot be recognized";
+        } else {
+            return String.format("ERROR\n-------\nThe product cannot be found: %s", validationResult.barcode);
+        }
+    }
+
+    public static ValidateErrorResult ValidateBarcodes(List<String> selectedBarcodes, List<Product> products) {
+        if (selectedBarcodes == null) {
+            return new ValidateErrorResult("", ValidateErrorType.INVALID_BARCODE);
+        }
+
+        ValidateErrorResult validationResult = new ValidateErrorResult("", ValidateErrorType.VALID);
+        for (String barcodeAndAmount : selectedBarcodes) {
+            if (!isValidBarcodeAndAmount(barcodeAndAmount)) {
+                validationResult.errorType = ValidateErrorType.INVALID_BARCODE;
+                validationResult.barcode = barcodeAndAmount;
+                break;
+            }
+
+            String barcode = barcodeAndAmount.split("-", 2)[0];
+            if (!ContainsInProducts(barcode, products)) {
+                validationResult.errorType = ValidateErrorType.PRODUCT_NOT_FOUND;
+                validationResult.barcode = barcode;
+                break;
+            }
+        }
+
+        return validationResult;
+    }
+
+    private static boolean ContainsInProducts(String barcode, List<Product> products) {
+        for (Product product : products) {
+            if (Objects.equals(product.barcode, barcode)) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    private static boolean isValidBarcodeAndAmount(String barcodeAndAmount) {
+        String[] res = barcodeAndAmount.split("-");
+        if (res.length == 0 || res.length > 2) {
+            return false;
+        }
+
+        if (!isOnlyContainsUpperCaseOrNumber(res[0])) {
+            return false;
+        }
+
+        if (res.length == 2) {
+            return isValidProductAmount(res[1]);
+        }
+
+        return true;
+    }
+
+    private static boolean isOnlyContainsUpperCaseOrNumber(String barcode) {
+        for (int i = 0; i < barcode.length(); i++) {
+            if (Character.isUpperCase(barcode.charAt(i)) || Character.isDigit(barcode.charAt(i))) {
+                continue;
+            }
+            return false;
+        }
+
+        return true;
+    }
+
+    private static boolean isValidProductAmount(String amountStr) {
+        try {
+            int amount = Integer.parseInt(amountStr);
+            if (amount <= 0 || amount > 99) {
+                return false;
+            }
+        } catch (NumberFormatException e) {
+            return false;
+        }
+
+        return  true;
+    }
+}
diff --git a/barcode-tasking-sample/src/main/java/org/example/Main.java b/barcode-tasking-sample/src/main/java/org/example/Main.java
new file mode 100644
index 0000000000000000000000000000000000000000..407f157bcb0852a527a500994d9e16a54f520f3f
--- /dev/null
+++ b/barcode-tasking-sample/src/main/java/org/example/Main.java
@@ -0,0 +1,7 @@
+package org.example;
+
+public class Main {
+    public static void main(String[] args) {
+        System.out.println("Hello world!");
+    }
+}
\ No newline at end of file
diff --git a/barcode-tasking-sample/src/main/java/org/example/Product.java b/barcode-tasking-sample/src/main/java/org/example/Product.java
new file mode 100644
index 0000000000000000000000000000000000000000..6756c2107e419d801a229c4027cc5ff29bf7279a
--- /dev/null
+++ b/barcode-tasking-sample/src/main/java/org/example/Product.java
@@ -0,0 +1,12 @@
+package org.example;
+
+public class Product {
+    public final String name;
+    public final double price;
+    public final String barcode;
+    public Product(String name, double price, String barcode) {
+        this.name = name;
+        this.price = price;
+        this.barcode = barcode;
+    }
+}
diff --git a/barcode-tasking-sample/src/main/java/org/example/Receipt.java b/barcode-tasking-sample/src/main/java/org/example/Receipt.java
new file mode 100644
index 0000000000000000000000000000000000000000..9548643986a5ed71036ee1110a65e18baf4a05f1
--- /dev/null
+++ b/barcode-tasking-sample/src/main/java/org/example/Receipt.java
@@ -0,0 +1,22 @@
+package org.example;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class Receipt {
+    private final List<ReceiptProduct> receiptProductList = new ArrayList<>();
+    private double totalPrice;
+
+    public void addProduct(ReceiptProduct product) {
+        receiptProductList.add(product);
+        totalPrice += product.totalPrice;
+    }
+
+    public List<ReceiptProduct> getReceiptProductList() {
+        return receiptProductList;
+    }
+
+    public double getTotalPrice() {
+        return totalPrice;
+    }
+}
\ No newline at end of file
diff --git a/barcode-tasking-sample/src/main/java/org/example/ReceiptCreator.java b/barcode-tasking-sample/src/main/java/org/example/ReceiptCreator.java
new file mode 100644
index 0000000000000000000000000000000000000000..6051d9ad3721aa83922ef31be5a09d3833a18e4b
--- /dev/null
+++ b/barcode-tasking-sample/src/main/java/org/example/ReceiptCreator.java
@@ -0,0 +1,31 @@
+package org.example;
+
+import java.util.List;
+
+public class ReceiptCreator {
+    public static Receipt CreateReceipt(List<Barcode> groupedBarcodes, List<Product> products) {
+        Receipt receipt = new Receipt();
+        for (Barcode barcode : groupedBarcodes) {
+            Product product = GetProductWithBarcode(products, barcode.barcode);
+            if (product == null) {
+                continue;
+            }
+
+            double totalPrice = product.price * barcode.amount;
+            ReceiptProduct receiptProduct = new ReceiptProduct(product.name, barcode.amount, product.price, totalPrice);
+            receipt.addProduct(receiptProduct);
+        }
+
+        return receipt;
+    }
+
+    private static Product GetProductWithBarcode(List<Product> products, String barcode) {
+        for (Product product : products) {
+            if (product.barcode.equals(barcode)) {
+                return product;
+            }
+        }
+
+        return null;
+    }
+}
diff --git a/barcode-tasking-sample/src/main/java/org/example/ReceiptFormatter.java b/barcode-tasking-sample/src/main/java/org/example/ReceiptFormatter.java
new file mode 100644
index 0000000000000000000000000000000000000000..7a238e27802517a73c7534b6bb0d5326d49c43d4
--- /dev/null
+++ b/barcode-tasking-sample/src/main/java/org/example/ReceiptFormatter.java
@@ -0,0 +1,15 @@
+package org.example;
+
+public class ReceiptFormatter {
+    public static String FormatReceipt(Receipt receipt) {
+        StringBuilder stringBuilder = new StringBuilder();
+        stringBuilder.append("Receipt\n-------\n");
+        for (ReceiptProduct product : receipt.getReceiptProductList()) {
+            stringBuilder.append(String.format("Name: %s, Amount: %d, Price: %.2f, Total: %.2f\n",
+                    product.name, product.amount, product.price, product.totalPrice));
+        }
+        stringBuilder.append(String.format("-------\nTotal: %.2f", receipt.getTotalPrice()));
+
+        return stringBuilder.toString();
+    }
+}
diff --git a/barcode-tasking-sample/src/main/java/org/example/ReceiptPrinter.java b/barcode-tasking-sample/src/main/java/org/example/ReceiptPrinter.java
new file mode 100644
index 0000000000000000000000000000000000000000..4b2f33f01b048853005c4309ad85f3df32a2bcc6
--- /dev/null
+++ b/barcode-tasking-sample/src/main/java/org/example/ReceiptPrinter.java
@@ -0,0 +1,21 @@
+package org.example;
+
+import java.util.List;
+
+public class ReceiptPrinter {
+    public static String CreateValidReceipt(List<String> selectedBarcodes, List<Product> products) {
+        List<Barcode> barcodesAndAmount = BarcodesParser.ParseBarcodes(selectedBarcodes);
+        List<Barcode> groupedBarcodes = BarcodesParser.GroupBarcodes(barcodesAndAmount);
+        Receipt receipt = ReceiptCreator.CreateReceipt(groupedBarcodes, products);
+        return ReceiptFormatter.FormatReceipt(receipt);
+    }
+
+    public static String PrintReceipt(List<String> selectedBarcodes, List<Product> products) {
+        ValidateErrorResult validationResult = BarcodesValidation.ValidateBarcodes(selectedBarcodes, products);
+        if (validationResult.errorType != ValidateErrorType.VALID) {
+            return BarcodesValidation.CreateErrorReceipt(validationResult);
+        }
+
+        return CreateValidReceipt(selectedBarcodes, products);
+    }
+}
diff --git a/barcode-tasking-sample/src/main/java/org/example/ReceiptProduct.java b/barcode-tasking-sample/src/main/java/org/example/ReceiptProduct.java
new file mode 100644
index 0000000000000000000000000000000000000000..9438f955f3b90bc99b1d969a5596e40adeea1dfe
--- /dev/null
+++ b/barcode-tasking-sample/src/main/java/org/example/ReceiptProduct.java
@@ -0,0 +1,34 @@
+package org.example;
+
+import java.util.Objects;
+
+public class ReceiptProduct {
+    public final String name;
+    public final int amount;
+    public final double price;
+    public final double totalPrice;
+
+    public ReceiptProduct(String name, int amount, double price, double totalPrice) {
+        this.name = name;
+        this.amount = amount;
+        this.price = price;
+        this.totalPrice = totalPrice;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) return true;
+        if (obj == null || getClass() != obj.getClass()) return false;
+
+        ReceiptProduct product = (ReceiptProduct) obj;
+        return Objects.equals(name, product.name) &&
+                amount == product.amount &&
+                0 == Double.compare(price, product.price) &&
+                0 == Double.compare(totalPrice, product.totalPrice);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(name, amount, price, totalPrice);
+    }
+}
diff --git a/barcode-tasking-sample/src/main/java/org/example/ValidateErrorResult.java b/barcode-tasking-sample/src/main/java/org/example/ValidateErrorResult.java
new file mode 100644
index 0000000000000000000000000000000000000000..a41d0de1817a76483d685413b962ad636cfdbf48
--- /dev/null
+++ b/barcode-tasking-sample/src/main/java/org/example/ValidateErrorResult.java
@@ -0,0 +1,10 @@
+package org.example;
+
+public class ValidateErrorResult {
+    public String barcode;
+    public ValidateErrorType errorType;
+    public ValidateErrorResult(String barcode, ValidateErrorType errorType) {
+        this.barcode = barcode;
+        this.errorType = errorType;
+    }
+}
diff --git a/barcode-tasking-sample/src/main/java/org/example/ValidateErrorType.java b/barcode-tasking-sample/src/main/java/org/example/ValidateErrorType.java
new file mode 100644
index 0000000000000000000000000000000000000000..3920acb84ff737edab36ceee2d4979a938148ee6
--- /dev/null
+++ b/barcode-tasking-sample/src/main/java/org/example/ValidateErrorType.java
@@ -0,0 +1,7 @@
+package org.example;
+
+public enum ValidateErrorType {
+    VALID,
+    INVALID_BARCODE,
+    PRODUCT_NOT_FOUND
+}
diff --git a/barcode-tasking-sample/src/test/java/BarcodesParserTest.java b/barcode-tasking-sample/src/test/java/BarcodesParserTest.java
new file mode 100644
index 0000000000000000000000000000000000000000..04bed015a2268370b67029d176c8a7854be47b81
--- /dev/null
+++ b/barcode-tasking-sample/src/test/java/BarcodesParserTest.java
@@ -0,0 +1,63 @@
+import org.example.Barcode;
+import org.example.BarcodesParser;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class BarcodesParserTest {
+    @Test
+    void should_get_empty_grouped_barcodes_if_no_barcode() {
+        // Given
+        List<Barcode> barcodesAndAmount = new ArrayList<>();
+
+        // When
+        List<Barcode> groupedBarcodes = BarcodesParser.GroupBarcodes(barcodesAndAmount);
+
+        // Then
+        Assertions.assertTrue(groupedBarcodes.isEmpty());
+    }
+
+    @Test
+    void should_get_grouped_barcodes_if_contains_same_barcodes() {
+        // Given
+        List<Barcode> barcodesAndAmount = new ArrayList<>();
+        barcodesAndAmount.add(new Barcode("ITEM000001", 1));
+        barcodesAndAmount.add(new Barcode("ITEM000001", 1));
+
+        List<Barcode> succeedBarcodes = List.of(new Barcode("ITEM000001", 1));
+
+        // When
+        List<Barcode> groupedBarcodes = BarcodesParser.GroupBarcodes(barcodesAndAmount);
+
+        // Then
+        Assertions.assertEquals(succeedBarcodes, groupedBarcodes);
+    }
+
+    @Test
+    void should_get_empty_barcodes_and_amount_if_no_selected_barcodes() {
+        // Given
+        List<String> selectedBarcodes = new ArrayList<>();
+
+        // When
+        List<Barcode> barcodesAndAmount = BarcodesParser.ParseBarcodes(selectedBarcodes);
+
+        // Then
+        Assertions.assertTrue(barcodesAndAmount.isEmpty());
+    }
+
+    @Test
+    void should_get_barcodes_and_amount_if_contains_one_barcodes() {
+        // Given
+        List<String> selectedBarcodes = List.of("ITEM000001");
+
+        List<Barcode> succeedBarcodesAndAmount = List.of(new Barcode("ITEM000001", 1));
+
+        // When
+        List<Barcode> barcodesAndAmount = BarcodesParser.ParseBarcodes(selectedBarcodes);
+
+        // Then
+        Assertions.assertEquals(succeedBarcodesAndAmount, barcodesAndAmount);
+    }
+}
diff --git a/barcode-tasking-sample/src/test/java/BarcodesValidationTest.java b/barcode-tasking-sample/src/test/java/BarcodesValidationTest.java
new file mode 100644
index 0000000000000000000000000000000000000000..cef4cf67586ac918738c2bb4efe0d1da3690c936
--- /dev/null
+++ b/barcode-tasking-sample/src/test/java/BarcodesValidationTest.java
@@ -0,0 +1,76 @@
+import org.example.BarcodesValidation;
+import org.example.Product;
+import org.example.ValidateErrorResult;
+import org.example.ValidateErrorType;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+import java.util.List;
+
+public class BarcodesValidationTest {
+    @Test
+    void should_get_error_receipt_content_if_error_type_is_invalid_barcode() {
+        // Given
+        ValidateErrorResult validationResult = new ValidateErrorResult("ASDF1234$$$$", ValidateErrorType.INVALID_BARCODE);
+
+        // When
+        String receiptContent = BarcodesValidation.CreateErrorReceipt(validationResult);
+
+        // Then
+        Assertions.assertEquals(receiptContent, "ERROR\n-------\nThe barcode cannot be recognized");
+    }
+
+    @Test
+    void should_get_error_receipt_content_if_error_type_is_product_not_found() {
+        // Given
+        ValidateErrorResult validationResult = new ValidateErrorResult("ITEM000002", ValidateErrorType.PRODUCT_NOT_FOUND);
+
+        // When
+        String receiptContent = BarcodesValidation.CreateErrorReceipt(validationResult);
+
+        // Then
+        Assertions.assertEquals(receiptContent, "ERROR\n-------\nThe product cannot be found: ITEM000002");
+    }
+
+    @Test
+    void should_get_error_validation_result_if_barcode_has_invalid_character() {
+        // Given
+        List<String> selectedBarcodes = List.of("ASDF1234$$$$");
+        List<Product> products = List.of(new Product("Cola", 3.00, "ITEM000001"));
+
+        // When
+        ValidateErrorResult validationResult = BarcodesValidation.ValidateBarcodes(selectedBarcodes, products);
+
+        // Then
+        Assertions.assertEquals(validationResult.barcode, "ASDF1234$$$$");
+        Assertions.assertEquals(validationResult.errorType, ValidateErrorType.INVALID_BARCODE);
+    }
+
+    @Test
+    void should_get_error_validation_result_if_barcode_amount_over_99() {
+        // Given
+        List<String> selectedBarcodes = List.of("ITEM000001-100");
+        List<Product> products = List.of(new Product("Cola", 3.00, "ITEM000001"));
+
+        // When
+        ValidateErrorResult validationResult = BarcodesValidation.ValidateBarcodes(selectedBarcodes, products);
+
+        // Then
+        Assertions.assertEquals(validationResult.barcode, "ITEM000001-100");
+        Assertions.assertEquals(validationResult.errorType, ValidateErrorType.INVALID_BARCODE);
+    }
+
+    @Test
+    void should_get_error_validation_result_if_product_not_found() {
+        // Given
+        List<String> selectedBarcodes = List.of("ITEM000002");
+        List<Product> products = List.of(new Product("Cola", 3.00, "ITEM000001"));
+
+        // When
+        ValidateErrorResult validationResult = BarcodesValidation.ValidateBarcodes(selectedBarcodes, products);
+
+        // Then
+        Assertions.assertEquals(validationResult.barcode, "ITEM000002");
+        Assertions.assertEquals(validationResult.errorType, ValidateErrorType.PRODUCT_NOT_FOUND);
+    }
+}
diff --git a/barcode-tasking-sample/src/test/java/ReceiptCreatorTest.java b/barcode-tasking-sample/src/test/java/ReceiptCreatorTest.java
new file mode 100644
index 0000000000000000000000000000000000000000..f8a88aa1f7fb7936946f3307e94cd4d6bca55c5e
--- /dev/null
+++ b/barcode-tasking-sample/src/test/java/ReceiptCreatorTest.java
@@ -0,0 +1,57 @@
+import org.example.*;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class ReceiptCreatorTest {
+    @Test
+    void should_get_empty_receipt_if_empty_grouped_barcodes() {
+        // Given
+        List<Barcode> groupedBarcodes = new ArrayList<>();
+        List<Product> products = new ArrayList<>();
+        products.add(new Product("Cola", 3.00, "ITEM000001"));
+
+        // When
+        Receipt receipt = ReceiptCreator.CreateReceipt(groupedBarcodes, products);
+
+        // Then
+        Assertions.assertTrue(receipt.getReceiptProductList().isEmpty());
+        Assertions.assertEquals(receipt.getTotalPrice(), 0.00);
+    }
+
+    @Test
+    void should_get_empty_receipt_if_empty_products() {
+        // Given
+        List<Barcode> groupedBarcodes = new ArrayList<>();
+        groupedBarcodes.add(new Barcode("ITEM000001", 1));
+        List<Product> products = new ArrayList<>();
+
+        // When
+        Receipt receipt = ReceiptCreator.CreateReceipt(groupedBarcodes, products);
+
+        // Then
+        Assertions.assertTrue(receipt.getReceiptProductList().isEmpty());
+        Assertions.assertEquals(receipt.getTotalPrice(), 0.00);
+    }
+
+    @Test
+    void should_get_receipt_if_one_grouped_barcodes() {
+        // Given
+        List<Barcode> groupedBarcodes = new ArrayList<>();
+        groupedBarcodes.add(new Barcode("ITEM000001", 1));
+        List<Product> products = new ArrayList<>();
+        products.add(new Product("Cola", 3.00, "ITEM000001"));
+
+        Receipt succeedReceipt = new Receipt();
+        succeedReceipt.addProduct(new ReceiptProduct("Cola", 1, 3.00, 3.00));
+
+        // When
+        Receipt receipt = ReceiptCreator.CreateReceipt(groupedBarcodes, products);
+
+        // Then
+        Assertions.assertEquals(receipt.getReceiptProductList(), succeedReceipt.getReceiptProductList());
+        Assertions.assertEquals(0, Double.compare(receipt.getTotalPrice(), 3.00));
+    }
+}
diff --git a/barcode-tasking-sample/src/test/java/ReceiptFormatterTest.java b/barcode-tasking-sample/src/test/java/ReceiptFormatterTest.java
new file mode 100644
index 0000000000000000000000000000000000000000..a77c729ab956f2d406179372f01b448478210420
--- /dev/null
+++ b/barcode-tasking-sample/src/test/java/ReceiptFormatterTest.java
@@ -0,0 +1,33 @@
+import org.example.Receipt;
+import org.example.ReceiptFormatter;
+import org.example.ReceiptProduct;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+public class ReceiptFormatterTest {
+    @Test
+    void should_get_empty_receipt_content_if_receipt_contains_no_products() {
+        // Given
+        Receipt emptyReceipt = new Receipt();
+
+        // When
+        String receiptContent = ReceiptFormatter.FormatReceipt(emptyReceipt);
+
+        // Then
+        Assertions.assertEquals(receiptContent, "Receipt\n-------\n-------\nTotal: 0.00");
+    }
+
+    @Test
+    void should_get_receipt_content_if_receipt_contains_one_products() {
+        // Given
+        ReceiptProduct product = new ReceiptProduct("Cola", 3, 3.00, 9.00);
+        Receipt receipt = new Receipt();
+        receipt.addProduct(product);
+
+        // When
+        String receiptContent = ReceiptFormatter.FormatReceipt(receipt);
+
+        // Then
+        Assertions.assertEquals(receiptContent, "Receipt\n-------\nName: Cola, Amount: 3, Price: 3.00, Total: 9.00\n-------\nTotal: 9.00");
+    }
+}
diff --git a/barcode-tasking-sample/src/test/java/ReceiptPrinterTest.java b/barcode-tasking-sample/src/test/java/ReceiptPrinterTest.java
new file mode 100644
index 0000000000000000000000000000000000000000..33479776af74d20c9de17157b992d5f117dede2a
--- /dev/null
+++ b/barcode-tasking-sample/src/test/java/ReceiptPrinterTest.java
@@ -0,0 +1,87 @@
+import org.example.Product;
+import org.example.ReceiptPrinter;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class ReceiptPrinterTest {
+    @Test
+    void should_get_empty_receipt_content_if_contains_no_selected_barcodes() {
+        // Given
+        List<String> selectedBarcodes = new ArrayList<>();
+        List<Product> products = List.of(new Product("Cola", 3.00, "ITEM000001"));
+
+        // When
+        String receiptContent = ReceiptPrinter.CreateValidReceipt(selectedBarcodes, products);
+
+        // Then
+        Assertions.assertEquals(receiptContent, "Receipt\n-------\n-------\nTotal: 0.00");
+    }
+
+    @Test
+    void should_get_empty_receipt_content_if_contains_no_products() {
+        // Given
+        List<String> selectedBarcodes = List.of("ITEM000001");
+        List<Product> products = new ArrayList<>();
+
+        // When
+        String receiptContent = ReceiptPrinter.CreateValidReceipt(selectedBarcodes, products);
+
+        // Then
+        Assertions.assertEquals(receiptContent, "Receipt\n-------\n-------\nTotal: 0.00");
+    }
+
+    @Test
+    void should_get_receipt_content_if_contains_one_selected_barcodes() {
+        // Given
+        List<String> selectedBarcodes = List.of("ITEM000001");
+        List<Product> products = List.of(new Product("Cola", 3.00, "ITEM000001"));
+
+        // When
+        String receiptContent = ReceiptPrinter.CreateValidReceipt(selectedBarcodes, products);
+
+        // Then
+        Assertions.assertEquals(receiptContent, "Receipt\n-------\nName: Cola, Amount: 1, Price: 3.00, Total: 3.00\n-------\nTotal: 3.00");
+    }
+
+    @Test
+    void should_get_error_receipt_content_if_contains_invalid_barcode() {
+        // Given
+        List<String> selectedBarcodes = List.of("ITEM000001$$$$");
+        List<Product> products = List.of(new Product("Cola", 3.00, "ITEM000001"));
+
+        // When
+        String receiptContent = ReceiptPrinter.PrintReceipt(selectedBarcodes, products);
+
+        // Then
+        Assertions.assertEquals(receiptContent, "ERROR\n-------\nThe barcode cannot be recognized");
+    }
+
+    @Test
+    void should_get_error_receipt_content_if_product_not_found() {
+        // Given
+        List<String> selectedBarcodes = List.of("ITEM000002");
+        List<Product> products = List.of(new Product("Cola", 3.00, "ITEM000001"));
+
+        // When
+        String receiptContent = ReceiptPrinter.PrintReceipt(selectedBarcodes, products);
+
+        // Then
+        Assertions.assertEquals(receiptContent, "ERROR\n-------\nThe product cannot be found: ITEM000002");
+    }
+
+    @Test
+    void should_get_receipt_content_if_valid_receipt() {
+        // Given
+        List<String> selectedBarcodes = List.of("ITEM000001");
+        List<Product> products = List.of(new Product("Cola", 3.00, "ITEM000001"));
+
+        // When
+        String receiptContent = ReceiptPrinter.PrintReceipt(selectedBarcodes, products);
+
+        // Then
+        Assertions.assertEquals(receiptContent, "Receipt\n-------\nName: Cola, Amount: 1, Price: 3.00, Total: 3.00\n-------\nTotal: 3.00");
+    }
+}