Q:

Caused by: org.flywaydb.core.api.FlywayException: Validate failed. Migration Checksum mismatch for migration 2

I tried to find the solution for the below problem, but none of them worked for me. I am developing Angular + Spring Boot application using MySQL + flyway. Please guide whats going wrong here.
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'flywayInitializer' defined in class path resource [org/springframework/boot/autoconfigure/flyway/FlywayAutoConfiguration$FlywayConfiguration.class]: Invocation of init method failed; nested exception is org.flywaydb.core.api.FlywayException: Validate failed. Migration Checksum mismatch for migration 2
-> Applied to database : 1499248173
-> Resolved locally    : -1729781252
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1578) ~[spring-beans-4.2.4.RELEASE.jar:4.2.4.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:545) ~[spring-beans-4.2.4.RELEASE.jar:4.2.4.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482) ~[spring-beans-4.2.4.RELEASE.jar:4.2.4.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) ~[spring-beans-4.2.4.RELEASE.jar:4.2.4.RELEASE]
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) ~[spring-beans-4.2.4.RELEASE.jar:4.2.4.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) ~[spring-beans-4.2.4.RELEASE.jar:4.2.4.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197) ~[spring-beans-4.2.4.RELEASE.jar:4.2.4.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:296) ~[spring-beans-4.2.4.RELEASE.jar:4.2.4.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197) ~[spring-beans-4.2.4.RELEASE.jar:4.2.4.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1054) ~[spring-context-4.2.4.RELEASE.jar:4.2.4.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:829) ~[spring-context-4.2.4.RELEASE.jar:4.2.4.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:538) ~[spring-context-4.2.4.RELEASE.jar:4.2.4.RELEASE]
    at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:118) ~[spring-boot-1.3.1.RELEASE.jar:1.3.1.RELEASE]
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:764) [spring-boot-1.3.1.RELEASE.jar:1.3.1.RELEASE]
    at org.springframework.boot.SpringApplication.doRun(SpringApplication.java:357) [spring-boot-1.3.1.RELEASE.jar:1.3.1.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:305) [spring-boot-1.3.1.RELEASE.jar:1.3.1.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1124) [spring-boot-1.3.1.RELEASE.jar:1.3.1.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1113) [spring-boot-1.3.1.RELEASE.jar:1.3.1.RELEASE]
    at com.boot.App.main(App.java:9) [classes/:na]
Caused by: org.flywaydb.core.api.FlywayException: Validate failed. Migration Checksum mismatch for migration 2
-> Applied to database : 1499248173
-> Resolved locally    : -1729781252
    at org.flywaydb.core.Flyway.doValidate(Flyway.java:1108) ~[flyway-core-3.2.1.jar:na]
    at org.flywaydb.core.Flyway.access$300(Flyway.java:62) ~[flyway-core-3.2.1.jar:na]
    at org.flywaydb.core.Flyway$1.execute(Flyway.java:1012) ~[flyway-core-3.2.1.jar:na]
    at org.flywaydb.core.Flyway$1.execute(Flyway.java:1006) ~[flyway-core-3.2.1.jar:na]
    at org.flywaydb.core.Flyway.execute(Flyway.java:1418) ~[flyway-core-3.2.1.jar:na]
    at org.flywaydb.core.Flyway.migrate(Flyway.java:1006) ~[flyway-core-3.2.1.jar:na]
    at org.springframework.boot.autoconfigure.flyway.FlywayMigrationInitializer.afterPropertiesSet(FlywayMigrationInitializer.java:66) ~[spring-boot-autoconfigure-1.3.1.RELEASE.jar:1.3.1.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1637) ~[spring-beans-4.2.4.RELEASE.jar:4.2.4.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1574) ~[spring-beans-4.2.4.RELEASE.jar:4.2.4.RELEASE]
    ... 18 common frames omitted

application.properties
logging.level.org.springframework.web=DEBUG

server.port=8080

spring.h2.console.enabled=true
spring.h2.console.path=/h2

## For H2 DB
#spring.datasource.url=jdbc:h2:file:~/dasboot
#spring.datasource.username=sa
#spring.datasource.password=
#spring.datasource.driver-class-name=org.h2.Driver

## For MYSQL DB
spring.datasource.url=jdbc:mysql://localhost:3306/dasboot
spring.datasource.username=root
spring.datasource.password=root
spring.datasource.driver-class-name=com.mysql.jdbc.Driver

spring.datasource.max-active=10
spring.datasource.max-idle=8
spring.datasource.max-wait=10000
spring.datasource.min-evictable-idle-time-millis=1000
spring.datasource.min-idle=8
spring.datasource.time-between-eviction-runs-millis=1

flyway.baseline-on-migrate=true
spring.jpa.hibernate.ddl-auto=false;

#datasource.flyway.url=jdbc:h2:file:~/dasboot
#datasource.flyway.username=sa
#datasource.flyway.password=
#datasource.flyway.driver-class-name=org.h2.Driver

datasource.flyway.url=jdbc:mysql://localhost:3306/dasboot
datasource.flyway.username=root
datasource.flyway.password=root
datasource.flyway.driver-class-name=com.mysql.jdbc.Driver

pom.xml
<parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.3.1.RELEASE</version>
    </parent>

    <name>das-boot</name>
    <url>http://maven.apache.org</url>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>com.h2database</groupId>
            <artifactId>h2</artifactId>
        </dependency>
        <dependency>
            <groupId>org.flywaydb</groupId>
            <artifactId>flyway-core</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>
    </dependencies>

V2__create_shipwreck.sql
-- For H2 DB
--CREATE TABLE SHIPWRECK(
--  ID INT AUTO_INCREMENT,
--  NAME VARCHAR(255),
--  DESCRIPTION VARCHAR(2000),
--  CONDITION VARCHAR(255),
--  DEPTH INT,
--  LATITUDE DOUBLE,
--  LONGITUDE DOUBLE,
--  YEAR_DISCOVERED INT
--);

CREATE TABLE `dasboot`.`shipwreck` (
  `ID` INT NOT NULL AUTO_INCREMENT,
  `NAME` VARCHAR(255) NULL,
  `DESCRIPTION` VARCHAR(2000) NULL,
  `CONDITION` VARCHAR(255) NULL,
  `DEPTH` INT NULL,
  `LATITUDE` DOUBLE NULL,
  `LONGITUDE` DOUBLE NULL,
  `YEAR_DISCOVERED` INT NULL,
  PRIMARY KEY (`ID`));

A:

Flyway is comparing the checksum of the SQL script with that of the previously run checksum.  This exception typically occurs if you change a SQL script that has already been applied by Flyway, thus causing a checksum mismatch.
If this is development, you can drop your database and start the migrations from scratch.
If you're in production, never edit SQL scripts that have already been applied.  Only create new SQL scripts going forward.

A:

The best solution would be to do these steps :

Delete the file called - V2__create_shipwreck.sql, clean and
build the project again. 
Run the project again, login into h2 and
delete the table called "schema_version".

drop table schema_version;

Now make V2__create_shipwreck.sql file with ddl and rerun the project again.
Do remember this, add version 4.1.2 for flyway-core in pom.xml like 
<dependency>
    <groupId>org.flywaydb</groupId>
    <artifactId>flyway-core</artifactId>
    <version>4.1.2</version>
</dependency>

It should work now. Hope this will help.

A:

I had the same issue and deleted the complete schema from the database, yet the issue remained.
I solved this by running the repair() command of flyway:
flyway.repair();

Alternatively with Flyway Maven plugin:
mvn flyway:repair

Maven plugin addition into pom.xml:
<plugin>
    <groupId>org.flywaydb</groupId>
    <artifactId>flyway-maven-plugin</artifactId>
    <version>5.2.4</version>
</plugin>

BTW: I did not find what exactly went wrong.
With Gradle (as per comment from Raf):
./gradlew flywayRepair

