Controller

package com.example.depdev.controller;

import com.example.depdev.entity.Task;
import com.example.depdev.repository.TaskRepository;
import com.example.depdev.service.TaskService;


import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;

import org.locationtech.jts.geom.Coordinate;
import org.locationtech.jts.geom.GeometryFactory;
import org.locationtech.jts.geom.Point;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

import javax.servlet.http.HttpServletRequest;

import java.util.ArrayList;
import java.util.List;

@Component
@Controller
@RequestMapping("/")
public class TestController {

    private TaskRepository taskRepository;

    @Autowired
    TaskService taskService;

    @Autowired
    public void setTaskRepository(TaskRepository taskRepository) {this.taskRepository = taskRepository;}

    @GetMapping("/alltasks")
    @ResponseBody
    public List allTasks() throws JsonProcessingException {

        GeometryFactory gf = new GeometryFactory();
        Double y = -36.829;
        Double x = 174.896;

        Task testTask = new Task();
        testTask.setId(new Long(01));
        testTask.setTitle("Test Task");
        Point p = gf.createPoint(new Coordinate(x, y));
        p.setSRID(4326);
        testTask.setLocation(p);
        taskRepository.save(testTask);

        ObjectMapper objectMapper = new ObjectMapper();

        String geoJson = objectMapper.writeValueAsString(testTask);

        List<Task> listTasks = new ArrayList<>();
        listTasks = taskService.findAll();
        return listTasks;
    }
}

Task

package com.example.depdev.entity;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.Table;
import com.bedatadriven.jackson.datatype.jts.serialization.GeometryDeserializer;
import com.bedatadriven.jackson.datatype.jts.serialization.GeometrySerializer;
import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
import com.fasterxml.jackson.databind.annotation.JsonSerialize;
import org.locationtech.jts.geom.Geometry;

@Entity
@Table(name = "task")
public class Task {

    public Task () {
    };

    @Id
    private Long id;
    private String title;
    @Column(columnDefinition = "geometry(Point,4326)")
    @JsonSerialize(using = GeometrySerializer.class)
    @JsonDeserialize(contentUsing = GeometryDeserializer.class)
    private Geometry location;