Building Java Projects with Maven

### Create the directory structure
```
mkdir -p src/main/java/hello
mkdir -p src/test/java/hello
```

### Create classes
`src/main/java/hello/HelloWorld.java`
```
package hello;

import org.joda.time.LocalTime;

public class HelloWorld {
    public static void main(String[] args) {
        LocalTime currentTime = new LocalTime();
        System.out.println("The current local time is: " + currentTime);
        Greeter greeter = new Greeter();
        System.out.println(greeter.sayHello());
    }
}
```
`src/main/java/hello/Greeter.java`
```
package hello;

public class Greeter {
    public String sayHello() {
        return "Hello world!";
    }
}
```
### Write a test
`src/test/java/hello/GreeterTest.java`
```
package hello;

import static org.hamcrest.CoreMatchers.containsString;
import static org.junit.Assert.*;

import org.junit.Test;

public class GreeterTest {

private Greeter greeter = new Greeter();

@Test
    public void greeterSaysHello() {
        assertThat(greeter.sayHello(), containsString("Hello"));
    }
}
```

### Create `pom.xml`
`pom.xml`
```
<?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 http://maven.apache.org/maven-v4_0_0.xsd">
	<modelVersion>4.0.0</modelVersion>

<groupId>org.springframework</groupId>
	<artifactId>gs-maven</artifactId>
	<packaging>jar</packaging>
	<version>0.1.0</version>

<dependencies>
		
		<dependency>
			<groupId>joda-time</groupId>
			<artifactId>joda-time</artifactId>
			<version>2.9.2</version>
		</dependency>
		
		
		<dependency>
			<groupId>junit</groupId>
			<artifactId>junit</artifactId>
			<version>4.12</version>
			<scope>test</scope>
		</dependency>
		
	</dependencies>

<build>
		<plugins>
			<plugin>
				<groupId>org.apache.maven.plugins</groupId>
				<artifactId>maven-shade-plugin</artifactId>
				<version>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>hello.HelloWorld</mainClass>
								</transformer>
							</transformers>
						</configuration>
					</execution>
				</executions>
			</plugin>
		</plugins>
	</build>

</project>
```

### Build Java code
Generate compiled `.class` files in the `target/classes` directory:
```
mvn compile
```
Run test:
```
mvn test
```
Compile Java code, run any tests, and finish by packaging the code up in a JAR file within the `target` directory:
```
mvn package
```
Install project’s JAR file to a repository of dependencies on the local machine (usually in `.m2/repository` directory in the home directory):
```
mvn install
```