// Third: sb.length() > 0, add delimiter + "" (sb becomes "middle,")
        assertEquals("middle,", result);
    }

    @Test
    @DisplayName("Should handle mix of empty and null elements")
    void testJoinWithMixedEmptyAndNull() {
        String result = StringUtil.join("-", "", null, "value", "", null);
        // First: "" (sb becomes "")

        controller.delayMillisBeforeProcessing = waittime;

        final List<Callable<Integer>> tasks = new ArrayList<Callable<Integer>>();
        // Mix of same and different hosts
        for (int i = 0; i < numTasks; i++) {
            final int index = i;
            tasks.add(new Callable<Integer>() {
                public Integer call() throws Exception {

1. Write failing test first
2. Understand root cause
3. Minimal changes
4. Verify no regressions

### When Refactoring

1. Preserve behavior
2. Keep tests green
3. Small incremental steps
4. Don't mix with new features

### Code Quality Checklist

- [ ] Java conventions followed
- [ ] JavaDoc for public APIs
- [ ] Tests pass (`mvn test`)
- [ ] No compiler warnings
- [ ] Proper exception handling

    /*
     * These arrays are set up to test that the comparator compares bytes within a word in the
     * correct order—in order words, that it doesn't mix up big-endian and little-endian. The first
     * array has a smaller element at one index, and then the second array has a smaller element at
     * the next.
     */

			Owner:  owners[i%len(owners)],
			Group:  true,
			Quorum: 3,
		}
		lris = append(lris, lri)
		locksHeld[resource] = []lockRequesterInfo{lri}
	}

	// Add a few concurrent read locks to the mix
	for i := range 50 {
		resource := fmt.Sprintf("bucket/get-object-%d", i)
		lri := lockRequesterInfo{
			Name:   resource,
			UID:    mustGetUUID(),
			Owner:  owners[i%len(owners)],
			Quorum: 2,
		}

            final int threadId = t;
            executor.submit(() -> {
                try {
                    for (int i = 0; i < operationsPerThread; i++) {
                        try {
                            // Mix of success and failure
                            final int iteration = i;
                            String result = circuitBreaker.executeWithCircuitBreaker(() -> {

 * {@code String} and a {@code String} to an {@code int} that treat the {@code int} as an unsigned
 * number.
 *
 * <p>Users of these utilities must be <i>extremely careful</i> not to mix up signed and unsigned
 * {@code int} values. When possible, it is recommended that the {@link UnsignedInteger} wrapper
 * class be used, at a small efficiency penalty, to enforce the distinction in the type system.
 *

 * {@code String} and a {@code String} to a {@code long} that treat the {@code long} as an unsigned
 * number.
 *
 * <p>Users of these utilities must be <i>extremely careful</i> not to mix up signed and unsigned
 * {@code long} values. When possible, it is recommended that the {@link UnsignedLong} wrapper class
 * be used, at a small efficiency penalty, to enforce the distinction in the type system.
 *

		cause:      err,
	}
}

func errParseCannotMixSqbAndWildcardInSelectList(err error) *s3Error {
	return &s3Error{
		code:       "ParseCannotMixSqbAndWildcardInSelectList",
		message:    "Cannot mix [] and * in the same expression in a SELECT list in SQL expression.",
		statusCode: 400,
		cause:      err,
	}
}

// ////////////////////////////////////////////////////////////////////////////////////
//

		t.Fatalf("create user: %v", err)
	}

	assocOp := clause.Association{Association: "Pets", Type: clause.OpCreate, Set: []clause.Assignment{{Column: clause.Column{Name: "name"}, Value: "mix-pet"}}}
	rows, err := gorm.G[User](DB).Where("id = ?", user.ID).Set(
		assocOp,
		clause.Assignment{Column: clause.Column{Name: "age"}, Value: 30},
	).Update(ctx)
	if err != nil {