Refine contribution #3932

* Add default methods in interfaces
* Update tests/Javadoc
* Optimize imports
* Apply code style formatting

spring-batch-core/src/main/java/org/springframework/batch/core/explore/JobExplorer.java

@@ -95,14 +95,17 @@ public interface JobExplorer {
 	JobInstance getJobInstance(@Nullable Long instanceId);
 
 	/**
-	 * @param jobName {@link String} name for the jobInstance.
-	 * @param jobParameters {@link JobParameters} parameters for the jobInstance.
-	 * @return the {@link JobInstance} with this name and parameters, or null
+	 * @param jobName {@link String} name of the job.
+	 * @param jobParameters {@link JobParameters} parameters for the job instance.
+	 * @return the {@link JobInstance} with the given name and parameters, or
+	 * {@code null}.
 	 *
 	 * @since 5.0
 	 */
 	@Nullable
-	JobInstance getJobInstance(String jobName, JobParameters jobParameters);
+	default JobInstance getJobInstance(String jobName, JobParameters jobParameters) {
+		throw new UnsupportedOperationException();
+	}
 
 	/**
 	 * Retrieve job executions by their job instance. The corresponding step executions

spring-batch-core/src/main/java/org/springframework/batch/core/explore/support/SimpleJobExplorer.java

@@ -40,7 +40,6 @@ import java.util.Set;
  * @author Will Schipp
  * @author Mahmoud Ben Hassine
  * @author Parikshit Dutta
- *
  * @see JobExplorer
  * @see JobInstanceDao
  * @see JobExecutionDao
@@ -191,8 +190,7 @@ public class SimpleJobExplorer implements JobExplorer {
 	/*
 	 * (non-Javadoc)
 	 *
-	 * @see
-	 * org.springframework.batch.core.explore.JobExplorer#getJobInstance(java
+	 * @see org.springframework.batch.core.explore.JobExplorer#getJobInstance(java
 	 * .lang.String, org.springframework.batch.core.JobParameters)
 	 */
 	@Nullable

spring-batch-core/src/main/java/org/springframework/batch/core/repository/JobRepository.java

@@ -188,14 +188,17 @@ public interface JobRepository {
 	void updateExecutionContext(JobExecution jobExecution);
 
 	/**
-	 * @param jobName {@link String} the name of the jobInstance
-	 * @param jobParameters {@link JobParameters} parameters identifying the {@link JobInstance}
-	 * @return the {@link JobInstance} with name and parameters, or null
+	 * @param jobName {@link String} name of the job.
+	 * @param jobParameters {@link JobParameters} parameters for the job instance.
+	 * @return the {@link JobInstance} with the given name and parameters, or
+	 * {@code null}.
 	 *
 	 * @since 5.0
 	 */
 	@Nullable
-	JobInstance getJobInstance(String jobName, JobParameters jobParameters);
+	default JobInstance getJobInstance(String jobName, JobParameters jobParameters) {
+		throw new UnsupportedOperationException();
+	}
 
 	/**
 	 * @param jobInstance {@link JobInstance} instance containing the step executions.

spring-batch-core/src/main/java/org/springframework/batch/core/repository/support/SimpleJobRepository.java

@@ -54,7 +54,6 @@ import java.util.List;
  * @author Mahmoud Ben Hassine
  * @author Baris Cubukcuoglu
  * @author Parikshit Dutta
- *
  * @see JobRepository
  * @see JobInstanceDao
  * @see JobExecutionDao

spring-batch-core/src/test/java/org/springframework/batch/core/configuration/xml/DummyJobRepository.java

@@ -33,7 +33,6 @@ import org.springframework.lang.Nullable;
  * @author David Turanski
  * @author Mahmoud Ben Hassine
  * @author Parikshit Dutta
- *
  * @since 2.0.1
  */
 public class DummyJobRepository implements JobRepository, BeanNameAware {

spring-batch-core/src/test/java/org/springframework/batch/core/explore/support/SimpleJobExplorerTests.java

@@ -19,10 +19,6 @@ package org.springframework.batch.core.explore.support;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertThrows;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNull;
-import static org.mockito.ArgumentMatchers.any;
-import static org.mockito.ArgumentMatchers.anyString;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
@@ -155,11 +151,18 @@ class SimpleJobExplorerTests {
 	}
 
 	@Test
-	public void testGetJobInstanceWithNameAndParameters() throws Exception {
-		when(jobInstanceDao.getJobInstance("job", new JobParameters())).thenReturn(jobInstance);
-		JobInstance jobInstance = jobExplorer.getJobInstance("job", new JobParameters());
-		verify(jobInstanceDao).getJobInstance(anyString(), any(JobParameters.class));
-		assertEquals(jobInstance, jobInstance);
+	public void testGetJobInstanceWithNameAndParameters() {
+		// given
+		String jobName = "job";
+		JobParameters jobParameters = new JobParameters();
+
+		// when
+		when(jobInstanceDao.getJobInstance(jobName, jobParameters)).thenReturn(this.jobInstance);
+		JobInstance jobInstance = jobExplorer.getJobInstance(jobName, jobParameters);
+
+		// then
+		verify(jobInstanceDao).getJobInstance(jobName, jobParameters);
+		assertEquals(this.jobInstance, jobInstance);
 	}
 
 	@Test

spring-batch-core/src/test/java/org/springframework/batch/core/repository/support/SimpleJobRepositoryTests.java

@@ -21,8 +21,6 @@ import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.mockito.ArgumentMatchers.any;
-import static org.mockito.ArgumentMatchers.anyString;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
@@ -332,12 +330,19 @@ class SimpleJobRepositoryTests {
 		assertEquals(BatchStatus.STOPPED, jobExecution.getStatus());
 	}
 
-
 	@Test
-	public void testGetJobInstanceWithNameAndParameters() throws Exception {
-		when(jobInstanceDao.getJobInstance("job", new JobParameters())).thenReturn(jobInstance);
-		JobInstance jobInstance = jobRepository.getJobInstance("job", new JobParameters());
-		verify(jobInstanceDao).getJobInstance(anyString(), any(JobParameters.class));
-		assertEquals(jobInstance, jobInstance);
+	public void testGetJobInstanceWithNameAndParameters() {
+		// given
+		String jobName = "job";
+		JobParameters jobParameters = new JobParameters();
+
+		// when
+		when(jobInstanceDao.getJobInstance(jobName, jobParameters)).thenReturn(this.jobInstance);
+		JobInstance jobInstance = jobRepository.getJobInstance(jobName, jobParameters);
+
+		// then
+		verify(jobInstanceDao).getJobInstance(jobName, jobParameters);
+		assertEquals(this.jobInstance, jobInstance);
 	}
+
 }

spring-batch-integration/src/test/java/org/springframework/batch/integration/JobRepositorySupport.java

@@ -48,14 +48,17 @@ public class JobRepositorySupport implements JobRepository {
 
 	/*
 	 * (non-Javadoc)
-	 * @see org.springframework.batch.core.repository.JobRepository#getJobInstance(java.lang.String,
-	 * org.springframework.batch.core.JobParameters)
+	 *
+	 * @see
+	 * org.springframework.batch.core.repository.JobRepository#getJobInstance(java.lang.
+	 * String, org.springframework.batch.core.JobParameters)
 	 */
 	public JobInstance getJobInstance(String jobName, JobParameters jobParameters) {
 		return null;
 	}
 
-	/* (non-Javadoc)
+	/*
+	 * (non-Javadoc)
 	 *
 	 * @see
 	 * org.springframework.batch.core.repository.JobRepository#getLastStepExecution(org.