import java.lang.reflect.Field;
import java.lang.reflect.Method;


public class Test {
    public static void main(String[] args) {
        Student s1 = new Student();
        Class c1 = s1.getClass();
        System.out.println(c1.getName());
        // Получить массив методов
        Method[] methods = c1.getDeclaredMethods();
        for (Method method : methods)
            System.out.println(method.getName());
        //Получить массив полей
        Field[] fields = c1.getDeclaredFields();
        for (Field field : fields)
            System.out.println(field.getName());
    }
}


class Student {
    private String name;
    private int number;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getNumber() {
        return number;
    }

    public void setNumber(int number) {
        this.number = number;
    }
}

class Person {
    int id;
    String name;

    public Person(int id, String name) {
        this.id = id;
        this.name = name;
    }
}

public class PersonBuilder {
    private static Person buildPerson(int id, String name) {
        return new Person(id, name);
    }

    public static void main(String[] args) {
        int id = 23;
        String name = "John";
        Person person = null;
        person = buildPerson(id, name);
    }
}

Student student = new Student("S1");
Student student2 = new Student("S2");
student2 = null;

package com.example;

class Main {

  public static void main(String[] args) {
    String inputStr = args[0];
    String hash = calculateMD5Hash(inputStr);
    System.out.println(hash);
  }

  private static String calculateMD5Hash(String input) {
    // implementation...
  }
}

package com.example;

import com.apache.HashUtil;

class Main {

  public static void main(String[] args) {
    String inputStr = args[0];
    String hash = HashUtil.md5(inputStr);
    System.out.println(hash);
  }
}

javac Main.java       # компиляция в byte-код (файл с расширением .class)
java com.example.Main # запуска программы (указываем название класса вместе с пакетом)

javac Main.java
java -classpath . com.example.Main # несколько директорий classpath можно разделять знаком ;

<dependencies>
  <dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-lang3</artifactId>
    <version>3.12.0</version>
  </dependency>
</dependencies>

mvn archetype:generate \
	-DgroupId=com.mts.meta \
	-DartifactId=student-project \
	-DarchetypeArtifactId=maven-archetype-quickstart \
	-DinteractiveMode=false

<build>
   
    <plugins>
       
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-shade-plugin</artifactId>
        <version>3.5.0</version>
        <executions>
          <execution>
            <goals>
              <goal>shade</goal>
            </goals>
            <configuration>
              <shadedArtifactAttached>true</shadedArtifactAttached>
              <transformers>
                <transformer implementation=
                  "org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                  <mainClass>org.example.Main</mainClass>
                </transformer>
              </transformers>
            </configuration>
          </execution>
        </executions>
      </plugin>
       
    </plugins>
   
</build>

mvn package

java -jar my-test-project-1.0-SNAPSHOT-shaded.jar

*#
*.iml
*.ipr
*.iws
*.jar
*.sw?
*~
.#*
.*.md.html
.DS_Store
.attach_pid*
.classpath
.factorypath
.gradle
.idea
.metadata
.project
.recommenders
.settings
.springBeans
.vscode
/code
MANIFEST.MF
_site/
activemq-data
bin
build
!/**/src/**/bin
!/**/src/**/build
build.log
dependency-reduced-pom.xml
dump.rdb
interpolated*.xml
lib/
manifest.yml
out
overridedb.*
target
.flattened-pom.xml
secrets.yml
.gradletasknamecache
.sts4-cache

* text=auto

name: Java CI with Maven

on:
  push:
    branches: [ "master" ]
  pull_request:
    branches: [ "master" ]

jobs:
  build:

    runs-on: ubuntu-latest

    steps:
      - uses: actions/checkout@v3
      - name: Set up JDK 17
        uses: actions/setup-java@v3
        with:
          java-version: '17'
          distribution: 'temurin'
          cache: maven
      - name: Build with Maven
        run: mvn package