First Entity

Create a package org.example.domain and in that create an entity bean like Customer.java 

package org.example.domain;

import jakarata.persistence.Id;
import jakarata.persistence.Entity;

@Entity
public class Customer {

  @Id
  long id;

  String name;

  // getters and setters
}
  

package org.example.domain

import jakarata.persistence.Entity
import jakarata.persistence.Id

@Entity
class Customer {

  @Id
  var id: Long = 0

  var name: String? = null

}

First Test

Create a test in src/test like CustomerTest.java 

package org.example.domain;

import org.junit.Test;

import io.ebean.DB;
import io.ebean.Database;

public class CustomerTest {

 @Test
 public void insertFindDelete() {

  Customer customer = new Customer();
  customer.setName("Hello world");

  // insert the customer in the DB
  DB.save(customer);

  // Find by Id
  Customer foundHello = database.find(Customer.class, 1);

  // delete the customer
  DB.delete(customer);
 }
}
  

package org.example.domain

import io.ebean.DB
import org.junit.Test

class CustomerTest  {

  @Test
  fun insert_update_delete() {

    val customer = Customer()
    customer.name  = "Hello entity bean"

    // insert
    DB.save(customer)

    // find by Id
    var found = DB.find(Customer::class.java, 1);

    DB.delete(found);
  }
}

Run test

Run the test via the IDE and via Maven or Gradle. Check the logs to confirm you see the DDL and SQL that you expect.