Fix JacksonJsonEncoder for streams with more than 2 elements

spring-web-reactive/src/main/java/org/springframework/http/codec/json/JacksonJsonEncoder.java

@@ -83,7 +83,7 @@ public class JacksonJsonEncoder extends AbstractEncoder<Object> {
 			Mono<DataBuffer> startArray =
 					Mono.just(bufferFactory.wrap(START_ARRAY_BUFFER));
 			Flux<DataBuffer> arraySeparators =
-					Mono.just(bufferFactory.wrap(SEPARATOR_BUFFER)).repeat();
+					Mono.fromSupplier(() -> bufferFactory.wrap(SEPARATOR_BUFFER)).repeat();
 			Mono<DataBuffer> endArray =
 					Mono.just(bufferFactory.wrap(END_ARRAY_BUFFER));
 

spring-web-reactive/src/test/java/org/springframework/http/codec/json/JacksonJsonEncoderTests.java

@@ -52,7 +52,11 @@ public class JacksonJsonEncoderTests extends AbstractDataBufferAllocatingTestCas
 
 	@Test
 	public void encode() {
-		Flux<Pojo> source = Flux.just(new Pojo("foofoo", "barbar"), new Pojo("foofoofoo", "barbarbar"));
+		Flux<Pojo> source = Flux.just(
+				new Pojo("foo", "bar"),
+				new Pojo("foofoo", "barbar"),
+				new Pojo("foofoofoo", "barbarbar")
+		);
 
 		ResolvableType type = ResolvableType.forClass(Pojo.class);
 		Flux<DataBuffer> output =
@@ -62,11 +66,15 @@ public class JacksonJsonEncoderTests extends AbstractDataBufferAllocatingTestCas
 				.subscribe(output)
 				.assertComplete()
 				.assertNoError()
-				.assertValuesWith(stringConsumer("["),
+				.assertValuesWith(
+						stringConsumer("["),
+						stringConsumer("{\"foo\":\"foo\",\"bar\":\"bar\"}"),
+						stringConsumer(","),
 						stringConsumer("{\"foo\":\"foofoo\",\"bar\":\"barbar\"}"),
 						stringConsumer(","),
 						stringConsumer("{\"foo\":\"foofoofoo\",\"bar\":\"barbarbar\"}"),
-						stringConsumer("]"));
+						stringConsumer("]")
+				);
 	}
 
 	@Test