Polish contribution

See gh-36932

spring-core/src/main/java/org/springframework/util/backoff/ExponentialBackOff.java

@@ -311,6 +311,8 @@ public class ExponentialBackOff implements BackOff {
 			long jitter = getJitter();
 			if (jitter > 0) {
 				long initialInterval = getInitialInterval();
+				// When initialInterval is 0 the interval never grows, so the scale factor
+				// stays at its baseline value of 1 and the full configured jitter is applied.
 				long applicableJitter = jitter * (initialInterval > 0 ? (interval / initialInterval) : 1);
 				long min = Math.max(interval - applicableJitter, initialInterval);
 				long max = Math.min(interval + applicableJitter, getMaxInterval());

spring-core/src/test/java/org/springframework/util/ExponentialBackOffTests.java

@@ -119,17 +119,15 @@ class ExponentialBackOffTests {
 		assertThatIllegalArgumentException().isThrownBy(() -> backOff.setMultiplier(0.9));
 	}
 
-	@Test
+	@Test  // gh-36932
 	void jitterWithZeroInitialInterval() {
-		// 'initialInterval = 0' and 'jitter > 0' are both individually accepted
-		// configurations, so their combination must not throw. With initialInterval
-		// of 0, the first nextBackOff() previously evaluated 'jitter * (0 / 0)',
-		// resulting in an integer division by zero.
 		ExponentialBackOff backOff = new ExponentialBackOff();
 		backOff.setInitialInterval(0);
 		backOff.setJitter(100);
-
 		BackOffExecution execution = backOff.start();
+
+		// 'initialInterval = 0' and 'jitter > 0' are both individually accepted
+		// configurations, so their combination must not throw.
 		assertThatNoException().isThrownBy(execution::nextBackOff);
 	}