Pre-requisite

Use Java 17 and above.

Goal

Reliably reproduce concurrent transactions scenario in developer test.

Approach

Get version of existing record, increment it by one and save. Multiple transactions will try to do the same. If we successfully manage to co-ordinate the transactions to read the same version and increment it by one, then we have successfully reproduced the scenario.

How to run tests

We used intellij idea's test configuration to repeat test until failure.

Result

For expected failure scenarios, tests failed within 1000 iterations. If it is taking too long, maybe stop and retry before your intellij hangs up. Or suggest us a better method.

Note

Transaction hook can help you gain visibility inside the transaction stages.

Example:

TransactionSynchronizationManager.registerSynchronization(
    new TransactionSynchronization() {
        @Override
        public void beforeCommit(boolean readOnly) {
        System.out.println(Thread.currentThread().getName() + " beforeCommit");
    }
});