JSONExample.java

package strimillinn.xperimental;

import java.io.File;
import java.io.IOException;
import java.nio.file.Files;
import java.util.List;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;

public class JSONExample {

	private static final Gson gson = new GsonBuilder().create();

	public static void main( String[] args ) {

		try {
			File f = new File( "test.json" );
			String jsonString = new String( Files.readAllBytes( f.toPath() ), "utf-8" );
			MyJSONFile objectGraph = gson.fromJson( jsonString, MyJSONFile.class );

			System.out.println( objectGraph.companies.get( 0 ).name );
		}
		catch( IOException e ) {
			throw new RuntimeException( "Dude. I'm doing example code, I can't be bothered with handling exceptions." );
		}
	}

	public static class MyJSONFile {
		public List<Company> companies;
	}

	public static class Company {
		public String name;
		public List<Department> departments;
	}

	public static class Department {
		public String name;
		public List<Employee> employees;
	}

	public static class Employee {
		public String name;
		public String emailAddress;
		public boolean fireAtNextrestructuring;
		public Integer howInterestingToTalkToFromOneToTen;
	}
}

test.json

{
  "companies": [
    {
      "name" : "JubbaCo",
      "departments" : [
        {
         "name" : "Logistics",
         "employees" : [
           {
            "name" : "Hugi"
           }
          ]
        }
        ]
    }
  ]
}