Is there something wrong with my method-naming in JPA?

I have a simple question about JpaRepository.

First, this is my Entity class.

package com.surveypedia.domain.pointhistory;

import lombok.Getter;
import lombok.NoArgsConstructor;

import javax.persistence.*;

@NoArgsConstructor
@Getter
@Entity
@Table(name = "pointhistory")
public class PointHistory {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Integer ph_code;

    @Column(nullable = false)
    private String email;

    @Column(nullable = false, name = "s_code")
    private Integer s_code;

    @Column(nullable = false)
    private Integer pointchange;

    @Column(nullable = false)
    @Enumerated(EnumType.STRING)
    private PointHistoryType ph_type;

    public PointHistory(String email, Integer s_code, Integer pointchange, PointHistoryType ph_type) {
        this.email = email;
        this.s_code = s_code;
        this.pointchange = pointchange;
        this.ph_type = ph_type;
    }
}

And below is my repository interface to do CRUD operations.

package com.surveypedia.domain.pointhistory;

import com.surveypedia.tools.SQL;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.Query;

import java.util.List;

public interface PointHistoryRepository extends JpaRepository<PointHistory, Integer> {

    List<PointHistory> findByEmail(String email);

    PointHistory findByS_codeAndEmailAndPh_type(Integer s_code, String email, PointHistoryType ph_type);
}

After starting my spring-boot project, I get this error :

java.lang.IllegalArgumentException: Failed to create query for method public abstract com.surveypedia.domain.pointhistory.PointHistory com.surveypedia.domain.pointhistory.PointHistoryRepository.findByS_codeAndEmailAndPh_type(java.lang.Integer,java.lang.String,com.surveypedia.domain.pointhistory.PointHistoryType)! No property s found for type PointHistory!

I tried findByEmailAndS_codeAndPh_type with proper arguments, but I got the same error log. What's the problem with my method there?

The problem is that underscore (_) is restricted to class hierarchies in spring-data-jpa mathod names. It's based on the simple convention of using camelCase in Java, which you're breaking.

Rename the field ph_code to phCode and s_code to sCode both in the entity and in the method name.