Failed to execute CommandLineRunner - Spring Batch

Question

Hi I am very new to Spring batch and I am getting the following exception which I am not able to resolve:

java.lang.IllegalStateException: Failed to execute CommandLineRunner
at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:800) [spring-boot-2.0.1.RELEASE.jar:2.0.1.RELEASE]
at org.springframework.boot.SpringApplication.callRunners(SpringApplication.java:781) [spring-boot-2.0.1.RELEASE.jar:2.0.1.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:335) [spring-boot-2.0.1.RELEASE.jar:2.0.1.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1255) [spring-boot-2.0.1.RELEASE.jar:2.0.1.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1243) [spring-boot-2.0.1.RELEASE.jar:2.0.1.RELEASE]
at com.demo.BatchDemo.main(KnpBatchApplication.java:16) [classes/:na]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_72]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_72]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_72]
at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_72]
at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:49) [spring-boot-devtools-2.0.1.RELEASE.jar:2.0.1.RELEASE]
Caused by: java.lang.IndexOutOfBoundsException: Index: 0, Size: 0
at java.util.ArrayList.rangeCheck(ArrayList.java:653) ~[na:1.8.0_72]
at java.util.ArrayList.get(ArrayList.java:429) ~[na:1.8.0_72]
at org.springframework.batch.core.JobParametersBuilder.getNextJobParameters(JobParametersBuilder.java:265) ~[spring-batch-core-4.0.1.RELEASE.jar:4.0.1.RELEASE]
at org.springframework.boot.autoconfigure.batch.JobLauncherCommandLineRunner.execute(JobLauncherCommandLineRunner.java:162) ~[spring-boot-autoconfigure-2.0.1.RELEASE.jar:2.0.1.RELEASE]
at org.springframework.boot.autoconfigure.batch.JobLauncherCommandLineRunner.executeLocalJobs(JobLauncherCommandLineRunner.java:179) ~[spring-boot-autoconfigure-2.0.1.RELEASE.jar:2.0.1.RELEASE]
at org.springframework.boot.autoconfigure.batch.JobLauncherCommandLineRunner.launchJobFromProperties(JobLauncherCommandLineRunner.java:134) ~[spring-boot-autoconfigure-2.0.1.RELEASE.jar:2.0.1.RELEASE]
at org.springframework.boot.autoconfigure.batch.JobLauncherCommandLineRunner.run(JobLauncherCommandLineRunner.java:128) ~[spring-boot-autoconfigure-2.0.1.RELEASE.jar:2.0.1.RELEASE]
at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:797) [spring-boot-2.0.1.RELEASE.jar:2.0.1.RELEASE]
... 10 common frames omitted

My Code here:

    @SpringBootApplication
    public class BatchDemo {
    public static void main(String args[])
    {
        SpringApplication.run(BatchDemo.class);
    }
}

I was able to resolve it by adding exclude = BatchAutoConfiguration.class. But I would like to find the actual cause and fix it.

I am not passing any commandline arguments and this exception doesn't occur all the time.

pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>demo</groupId>
<artifactId>demo_batch</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>demo_batch</name>
<url>http://maven.apache.org</url>
<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.0.1.RELEASE</version>
    <relativePath /> <!-- lookup parent from repository -->
</parent>
<properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
    <java.version>1.8</java.version>
</properties>
<dependencies>
    <dependency>
        <groupId>org.postgresql</groupId>
        <artifactId>postgresql</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-data-jpa</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.batch</groupId>
        <artifactId>spring-batch-core</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-core</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-context</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-batch</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-devtools</artifactId>
        <scope>runtime</scope>
    </dependency>
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.springframework.batch</groupId>
        <artifactId>spring-batch-test</artifactId>
        <scope>test</scope>
    </dependency>
</dependencies>

Answer 1

When you use @SpringBootApplication, Spring's autoConfiguration is enabled by default. Since you have spring batch dependencies loaded in your classpath, Spring Batch AutoConfiguration is enabled as well.

During application startup, Spring Batch's autoconfiguration (BatchAutoConfiguration) creates a Runner and it runs all the jobs defined in your BatchConfig.

You can disable this behavior by either setting spring.batch.job.enabled property to false in your application properties or by simply excluding the Autoconfiguration for Batch just like as you did.

Please refer here and here for more info.