How to run jar file of a maven project generated after build?

Question

I made a simple project with a few tests in it and I want to be able to launch tests on other computers. I built the project using Run As -> Maven build... -> Goals: package in Eclipse, and I found a jar file in target folder of the project. But when I try to run it in cmd using java -jar project.jar I get the following error:

Error: Main method not found in class com.example.TestPurchase, please define the main method as: public static void main(String[] args) or a JavaFX application class must extend javafx.application.Application

As far as I know, TestNG doesn't need any Main method, because of the annotations. That brings me to some questions:

Is something wrong with how I build my project?
Did I understand the method of executing tests via jar file correct?
Do I even have to use that jar file? Because I can run tests from command line being in project folder using mvn test

Here is my pom.xml file:

<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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.example</groupId>
<artifactId>Sightsy</artifactId>
<version>0.0.1-SNAPSHOT</version>
<properties>
    <java.version>1.8</java.version>
    <selenium.version>3.12.0</selenium.version>
    <testng.version>6.13.1</testng.version>
    <javafaker.version>0.14</javafaker.version>
    <guava.version>23.2-jre</guava.version>
    <extentreports.version>3.0.7</extentreports.version>
    <extenttestng.version>1.3.1</extenttestng.version>
    <assertj.version>3.8.0</assertj.version>
    <maven.compiler.version>3.7.0</maven.compiler.version>
    <commons.version>3.7</commons.version>
    <commons.io.version>2.6</commons.io.version>
</properties>

<dependencies>
    <dependency>
        <groupId>org.seleniumhq.selenium</groupId>
        <artifactId>selenium-java</artifactId>
        <version>${selenium.version}</version>
    </dependency>
    <dependency>
        <groupId>org.testng</groupId>
        <artifactId>testng</artifactId>
        <version>${testng.version}</version>
    </dependency>
    <dependency>
        <groupId>com.github.javafaker</groupId>
        <artifactId>javafaker</artifactId>
        <version>${javafaker.version}</version>
    </dependency>
    <dependency>
        <groupId>com.google.guava</groupId>
        <artifactId>guava</artifactId>
        <version>${guava.version}</version>
    </dependency>
    <dependency>
        <groupId>com.aventstack</groupId>
        <artifactId>extentreports</artifactId>
        <version>${extentreports.version}</version>
    </dependency>
    <dependency>
        <groupId>com.vimalselvam</groupId>
        <artifactId>testng-extentsreport</artifactId>
        <version>${extenttestng.version}</version>
    </dependency>
    <dependency>
        <groupId>org.assertj</groupId>
        <artifactId>assertj-core</artifactId>
        <version>${assertj.version}</version>
    </dependency>
    <dependency>
        <groupId>org.apache.commons</groupId>
        <artifactId>commons-lang3</artifactId>
        <version>${commons.version}</version>
    </dependency>
    <dependency>
        <groupId>commons-io</groupId>
        <artifactId>commons-io</artifactId>
        <version>${commons.io.version}</version>
    </dependency>
    <dependency>
        <groupId>com.opencsv</groupId>
        <artifactId>opencsv</artifactId>
        <version>3.4</version>
    </dependency>
    <dependency>
        <groupId>org.apache.poi</groupId>
        <artifactId>poi</artifactId>
        <version>3.12</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.apache.poi</groupId>
        <artifactId>poi-ooxml</artifactId>
        <version>3.12</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>com.amazonaws</groupId>
        <artifactId>aws-lambda-java-core</artifactId>
        <version>1.2.0</version>
    </dependency>
</dependencies>

<build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>${maven.compiler.version}</version>
            <configuration>
                <source>${java.version}</source>
                <target>${java.version}</target>
            </configuration>
        </plugin>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-shade-plugin</artifactId>
            <version>3.2.1</version>
            <executions>
                <execution>
                    <phase>package</phase>
                    <goals>
                        <goal>shade</goal>
                    </goals>
                    <configuration>
                        <transformers>
                            <transformer
                                implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                                <mainClass>com.example.TestPurchase</mainClass>
                            </transformer>
                        </transformers>
                    </configuration>
                </execution>
            </executions>
        </plugin>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-surefire-plugin</artifactId>
            <version>2.21.0</version>
            <configuration>
                <suiteXmlFiles>
                    <suiteXmlFile>src/main/resources/suites/testng.xml</suiteXmlFile>
                </suiteXmlFiles>
            </configuration>
        </plugin>
</plugins>
</build>

According to your build.xml, the jar doesn't contain the test files itself. For running the tests you just need to run "mvn test" assuming the other computers where you are planning to launch the tests have the codebase. — priyanka, Dec 13 '19 at 11:48
Ikeban's answer pretty much covers it. Should you ever find yourself in a situation where you do want code from the test path in a jar / as a Maven dependency: https://maven.apache.org/plugins/maven-jar-plugin/examples/create-test-jar.html — Gimby, Dec 13 '19 at 12:31
Usually you don't need a suites files in TestNG cause tests will be recognized based on their names like `*Test.java` for Unit tests and `*IT.java` for integration tests. Based on selenium I would vote for integration tests and you should use failsafe-plugin for running them and not surefire... — khmarbaise, Dec 13 '19 at 15:02

score 1 · Answer 1 · answered Dec 13 '19 at 12:14

I'm not familiar with TestNG framework, but my understanding is as following:

When "mvn package" is executed, your project is "validated", "compiled" and then "packed". During compilation, your code is changed to bytecode and can be interpreted (executed) by java virtual machine (JVM). This compiled code has only your application (I assume, that this is an application that is executed on Java server).

During the "package" step, these compiled classes (without tests) are put together in jar file. This jar file should contain only your application (again, without tests) - this is what you want because your jar file is smaller and contain only what is really needed.

Now when "mvn test" is executed, classes with test code are compiled and then executed. TestNG add the main function "automatically" so JVM knows what to do. Please note that running again "mvn package" will still NOT include these tests in jar file.

To address your questions directly: Ad 1. No Ad 2. Yes, "mvn test" is the correct way. Ad 3. No, you should not use jar file during testing. It is used later during deployment.

user218649 · Answer 2 · 2019-12-21T11:02:07.803

First of all, you must have a separate class with "main" method, where you will specify your xml suite files.

package com.example;
import java.util.ArrayList;
import java.util.List;
import org.testng.TestNG;
public class MainClass {
public static void main(String[] args) {
TestNG testSuite = new TestNG();
List<String> suites = new ArrayList<String>();
suites.add("path_to_your_xml_suite_file_in_target_folder");
testSuite.setTestSuites(suites);
testSuite.run();
 }
}

Then, you will need to specify this class with "main" method in configuration of maven-shade-plugin in pom.xml

<plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-shade-plugin</artifactId>
        <version>3.2.1</version>
        <executions>
            <execution>
                <phase>package</phase>
                <goals>
                    <goal>shade</goal>
                </goals>
                <configuration>
                    <transformers>
                        <transformer
                            implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                            <mainClass>com.example.TestNGMainClass</mainClass>
                        </transformer>
                    </transformers>
                </configuration>
            </execution>
        </executions>
    </plugin>

Then, when you will execute mvn build package without performing tests, you will have a fully working executable jar file in target folder, which you can launch in command line using java -jar name_of_you_jar_file.jar. It will need drivers and xml suite files to work

How to run jar file of a maven project generated after build?

2 Answers2