I've built some back ends with Node/Express and Go, but this is my first time trying to build one with Java/Spring.

I was told Flyway is the best tool for migrations. I got the SQL migrations working to get the schema set up for all my tables, now I'm trying to seed a user table with a Java-based migration.

Now when I call gradle flywayMigrate, I get this error:

loader constraint violation in interface itable initialization: when
resolving method
"db.migration.V2_1__Add_Users.migrate(Lorg/springframework/jdbc/core/JdbcTemplate;)V" 
the class loader (instance of java/net/URLClassLoader) of the current
class, db/migration/V2_1__Add_Users, and the class loader 
(instance of org/gradle/internal/classloader/VisitableURLClassLoader)
for interface
org/flywaydb/core/api/migration/spring/SpringJdbcMigration have
different Class objects for the type
org/springframework/jdbc/core/JdbcTemplate used in the signature

This is what I have in build.gradle:

buildscript {
    ext {
        springBootVersion = '1.5.2.RELEASE'
    }
    repositories {
        mavenCentral()
    }
    dependencies {
        classpath("org.springframework.boot:spring-boot-gradle-plugin:${springBootVersion}")
    }

}

plugins {
    id "org.flywaydb.flyway" version "4.1.2"
}

apply plugin: 'java'
apply plugin: 'eclipse'
apply plugin: 'org.springframework.boot'
apply plugin: 'project-report'

flyway {
    url = 'jdbc:mysql://localhost/upshift?serverTimezone=UTC'
    user = 'root'
    locations = ['db.migration']
}

version = '0.0.1-SNAPSHOT'
sourceCompatibility = 1.8

repositories {
    mavenCentral()
}


dependencies {
    compile('org.springframework.boot:spring-boot-starter-data-jpa')
    compile('org.flywaydb:flyway-core')
    compile('org.springframework.boot:spring-boot-starter-web')
    compile('org.springframework.boot:spring-boot-starter-security')
    compile("org.springframework:spring-jdbc")
    runtime('mysql:mysql-connector-java')
    testCompile('org.springframework.security:spring-security-test')
    testCompile('org.springframework.boot:spring-boot-starter-test')
}

And this is the java class I am trying to migrate with:

package db.migration;

import org.flywaydb.core.api.migration.spring.SpringJdbcMigration;
import org.springframework.jdbc.core.JdbcTemplate;

public class V2_1__Add_Users implements SpringJdbcMigration {
    public void migrate(JdbcTemplate jdbcTemplate) throws Exception {
        jdbcTemplate.execute("INSERT INTO users (email, password) VALUES ('test@test.com', 'test123')");
    }
}

Any idea what might be happening? I've poked around on here and done a fair bit of Googling but haven't found other similar examples. The whole reason I am doing a Java migration is so that I can try to bring in bCrypt to hash the passwords of my seeded users, but it's definitely possible that I'm thinking about this incorrectly. Any insight would be much appreciated!