# Undersized thread pool + AbortPolicy: 3 of 4 partitions rejected, and stuck forever

$ java -jar target/spring-batch-partitioning-1.0.0.jar --spring.profiles.active=reject \
    --partition.shards-dir=./data/shards-small --partition.grid-size=4 --partition.reject.pool-size=1

2026-09-14T09:11:18.181Z  INFO 3074 --- [           main] c.a.b.PartitioningDemoApplication        : The following 1 profile is active: "reject"
2026-09-14T09:11:21.361Z  INFO 3074 --- [           main] o.s.batch.core.step.AbstractStep         : Executing step: [ordersManagerStep]
2026-09-14T09:11:21.375Z  INFO 3074 --- [der-partition-1] o.s.batch.core.step.AbstractStep         : Executing step: [ordersWorkerStep:partition1]
2026-09-14T09:11:21.946Z  INFO 3074 --- [der-partition-1] o.s.batch.core.step.AbstractStep         : Step: [ordersWorkerStep:partition1] executed in 570ms
org.springframework.batch.core.job.JobExecutionException: Partition handler returned an unsuccessful step
2026-09-14T09:11:21.961Z  INFO 3074 --- [           main] o.s.batch.core.step.AbstractStep         : Step: [ordersManagerStep] executed in 601ms
JOB FINISHED: id=1 status=FAILED exitCode=FAILED

Only ordersWorkerStep:partition1 ever logs "Executing step" -- the other three were rejected by
the ThreadPoolTaskExecutor (corePoolSize=1, queueCapacity=0, AbortPolicy) before they could even
start, and TaskExecutorPartitionHandler swallows that TaskRejectedException into the rejected
StepExecution's failure list rather than printing it -- nothing named "TaskRejectedException" or
"Rejected" ever appears in this log. The job fails with the generic message above.

--- Querying BATCH_STEP_EXECUTION directly (org.h2.tools.Shell) shows what the log does not ---
$ java -cp h2-2.4.240.jar org.h2.tools.Shell -url jdbc:h2:file:./data/rejecttest -user sa -password "" \
    -sql "SELECT STEP_EXECUTION_ID, STEP_NAME, STATUS, EXIT_CODE FROM BATCH_STEP_EXECUTION ORDER BY STEP_EXECUTION_ID;"

STEP_EXECUTION_ID | STEP_NAME                   | STATUS    | EXIT_CODE
1                 | ordersManagerStep           | FAILED    | FAILED
2                 | ordersWorkerStep:partition3 | STARTING  | EXECUTING
3                 | ordersWorkerStep:partition2 | STARTING  | EXECUTING
4                 | ordersWorkerStep:partition1 | COMPLETED | COMPLETED
5                 | ordersWorkerStep:partition0 | STARTING  | EXECUTING

The manager step and the job both reach FAILED. The three rejected worker StepExecutions do not
-- they are parked at STARTING/EXECUTING permanently. Nothing in this job's lifecycle ever
transitions them again on its own.