Use lambdas and method references where appropriate

Author: fmbenhassine

spring-batch-core/src/main/java/org/springframework/batch/core/job/flow/support/state/SplitState.java

@@ -17,7 +17,6 @@
 
 import java.util.ArrayList;
 import java.util.Collection;
-import java.util.concurrent.Callable;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.Future;
 import java.util.concurrent.FutureTask;
@@ -89,12 +88,7 @@ public FlowExecutionStatus handle(final FlowExecutor executor) throws Exception
 
 		for (final Flow flow : flows) {
 
-			final FutureTask<FlowExecution> task = new FutureTask<>(new Callable<>() {
-				@Override
-				public FlowExecution call() throws Exception {
-					return flow.start(executor);
-				}
-			});
+			final FutureTask<FlowExecution> task = new FutureTask<>(() -> flow.start(executor));
 
 			tasks.add(task);
 

spring-batch-core/src/main/java/org/springframework/batch/core/partition/support/TaskExecutorPartitionHandler.java

@@ -18,7 +18,6 @@
 
 import java.util.HashSet;
 import java.util.Set;
-import java.util.concurrent.Callable;
 import java.util.concurrent.Future;
 import java.util.concurrent.FutureTask;
 
@@ -129,12 +128,9 @@ protected Set<StepExecution> doHandle(StepExecution managerStepExecution,
 	 * @return the task executing the given step
 	 */
 	protected FutureTask<StepExecution> createTask(final Step step, final StepExecution stepExecution) {
-		return new FutureTask<>(new Callable<>() {
-			@Override
-			public StepExecution call() throws Exception {
-				step.execute(stepExecution);
-				return stepExecution;
-			}
+		return new FutureTask<>(() -> {
+			step.execute(stepExecution);
+			return stepExecution;
 		});
 	}
 

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

@@ -37,7 +37,6 @@
 import org.springframework.batch.item.ExecutionContext;
 import org.springframework.core.serializer.Serializer;
 import org.springframework.jdbc.core.BatchPreparedStatementSetter;
-import org.springframework.jdbc.core.PreparedStatementSetter;
 import org.springframework.jdbc.core.RowMapper;
 import org.springframework.jdbc.support.lob.DefaultLobHandler;
 import org.springframework.jdbc.support.lob.LobHandler;
@@ -289,18 +288,15 @@ private void persistSerializedContext(final Long executionId, String serializedC
 			longContext = null;
 		}
 
-		getJdbcTemplate().update(getQuery(sql), new PreparedStatementSetter() {
-			@Override
-			public void setValues(PreparedStatement ps) throws SQLException {
-				ps.setString(1, shortContext);
-				if (longContext != null) {
-					lobHandler.getLobCreator().setClobAsString(ps, 2, longContext);
-				}
-				else {
-					ps.setNull(2, getClobTypeToUse());
-				}
-				ps.setLong(3, executionId);
+		getJdbcTemplate().update(getQuery(sql), ps -> {
+			ps.setString(1, shortContext);
+			if (longContext != null) {
+				lobHandler.getLobCreator().setClobAsString(ps, 2, longContext);
+			}
+			else {
+				ps.setNull(2, getClobTypeToUse());
 			}
+			ps.setLong(3, executionId);
 		});
 	}
 

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

@@ -373,12 +373,9 @@ public JobExecution getJobExecution(Long executionId) {
 	public Set<JobExecution> findRunningJobExecutions(String jobName) {
 
 		final Set<JobExecution> result = new HashSet<>();
-		RowCallbackHandler handler = new RowCallbackHandler() {
-			@Override
-			public void processRow(ResultSet rs) throws SQLException {
-				JobExecutionRowMapper mapper = new JobExecutionRowMapper();
-				result.add(mapper.mapRow(rs, 0));
-			}
+		RowCallbackHandler handler = rs -> {
+			JobExecutionRowMapper mapper = new JobExecutionRowMapper();
+			result.add(mapper.mapRow(rs, 0));
 		};
 		getJdbcTemplate().query(getQuery(GET_RUNNING_EXECUTIONS), handler, jobName);
 
@@ -455,27 +452,24 @@ private <T> void insertParameter(PreparedStatement preparedStatement, Long execu
 	 */
 	protected JobParameters getJobParameters(Long executionId) {
 		final Map<String, JobParameter<?>> map = new HashMap<>();
-		RowCallbackHandler handler = new RowCallbackHandler() {
-			@Override
-			public void processRow(ResultSet rs) throws SQLException {
-				String parameterName = rs.getString("PARAMETER_NAME");
-
-				Class<?> parameterType = null;
-				try {
-					parameterType = Class.forName(rs.getString("PARAMETER_TYPE"));
-				}
-				catch (ClassNotFoundException e) {
-					throw new RuntimeException(e);
-				}
-				String stringValue = rs.getString("PARAMETER_VALUE");
-				Object typedValue = conversionService.convert(stringValue, parameterType);
+		RowCallbackHandler handler = rs -> {
+			String parameterName = rs.getString("PARAMETER_NAME");
 
-				boolean identifying = rs.getString("IDENTIFYING").equalsIgnoreCase("Y");
+			Class<?> parameterType = null;
+			try {
+				parameterType = Class.forName(rs.getString("PARAMETER_TYPE"));
+			}
+			catch (ClassNotFoundException e) {
+				throw new RuntimeException(e);
+			}
+			String stringValue = rs.getString("PARAMETER_VALUE");
+			Object typedValue = conversionService.convert(stringValue, parameterType);
 
-				JobParameter<?> jobParameter = new JobParameter(typedValue, parameterType, identifying);
+			boolean identifying = rs.getString("IDENTIFYING").equalsIgnoreCase("Y");
 
-				map.put(parameterName, jobParameter);
-			}
+			JobParameter<?> jobParameter = new JobParameter(typedValue, parameterType, identifying);
+
+			map.put(parameterName, jobParameter);
 		};
 
 		getJdbcTemplate().query(getQuery(FIND_PARAMS_FROM_ID), handler, executionId);

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

@@ -221,12 +221,7 @@ public JobInstance getJobInstance(@Nullable Long instanceId) {
 	 */
 	@Override
 	public List<String> getJobNames() {
-		return getJdbcTemplate().query(getQuery(FIND_JOB_NAMES), new RowMapper<>() {
-			@Override
-			public String mapRow(ResultSet rs, int rowNum) throws SQLException {
-				return rs.getString(1);
-			}
-		});
+		return getJdbcTemplate().query(getQuery(FIND_JOB_NAMES), (rs, rowNum) -> rs.getString(1));
 	}
 
 	/*

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2006-2022 the original author or authors.
+ * Copyright 2006-2023 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -19,7 +19,6 @@
 import java.util.Properties;
 
 import org.aopalliance.intercept.MethodInterceptor;
-import org.aopalliance.intercept.MethodInvocation;
 import org.springframework.aop.framework.ProxyFactory;
 import org.springframework.aop.support.DefaultPointcutAdvisor;
 import org.springframework.aop.support.NameMatchMethodPointcut;
@@ -197,15 +196,12 @@ public JobRepository getObject() throws Exception {
 		TransactionInterceptor advice = new TransactionInterceptor((TransactionManager) this.transactionManager,
 				this.transactionAttributeSource);
 		if (this.validateTransactionState) {
-			DefaultPointcutAdvisor advisor = new DefaultPointcutAdvisor(new MethodInterceptor() {
-				@Override
-				public Object invoke(MethodInvocation invocation) throws Throwable {
-					if (TransactionSynchronizationManager.isActualTransactionActive()) {
-						throw new IllegalStateException("Existing transaction detected in JobRepository. "
-								+ "Please fix this and try again (e.g. remove @Transactional annotations from client).");
-					}
-					return invocation.proceed();
+			DefaultPointcutAdvisor advisor = new DefaultPointcutAdvisor((MethodInterceptor) invocation -> {
+				if (TransactionSynchronizationManager.isActualTransactionActive()) {
+					throw new IllegalStateException("Existing transaction detected in JobRepository. "
+							+ "Please fix this and try again (e.g. remove @Transactional annotations from client).");
 				}
+				return invocation.proceed();
 			});
 			NameMatchMethodPointcut pointcut = new NameMatchMethodPointcut();
 			pointcut.addMethodName("create*");

spring-batch-core/src/main/java/org/springframework/batch/core/scope/BatchScopeSupport.java

@@ -28,7 +28,6 @@
 import org.springframework.beans.factory.support.BeanDefinitionRegistry;
 import org.springframework.core.Ordered;
 import org.springframework.util.Assert;
-import org.springframework.util.StringValueResolver;
 
 /**
  * ScopeSupport.
@@ -174,12 +173,7 @@ protected static class Scopifier extends BeanDefinitionVisitor {
 		private final boolean scoped;
 
 		public Scopifier(BeanDefinitionRegistry registry, String scope, boolean proxyTargetClass, boolean scoped) {
-			super(new StringValueResolver() {
-				@Override
-				public String resolveStringValue(String value) {
-					return value;
-				}
-			});
+			super(value -> value);
 			this.registry = registry;
 			this.proxyTargetClass = proxyTargetClass;
 			this.scope = scope;