Deprecate StreamUtils.emptyInput()

Closes gh-29125

spring-context/src/test/java/org/springframework/scripting/support/ResourceScriptSourceTests.java

@@ -17,12 +17,12 @@
 package org.springframework.scripting.support;
 
 import java.io.IOException;
+import java.io.InputStream;
 
 import org.junit.jupiter.api.Test;
 
 import org.springframework.core.io.ByteArrayResource;
 import org.springframework.core.io.Resource;
-import org.springframework.util.StreamUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.mockito.BDDMockito.given;
@@ -60,7 +60,7 @@ public class ResourceScriptSourceTests {
 		// does not support File-based reading; delegates to InputStream-style reading...
 		//resource.getFile();
 		//mock.setThrowable(new FileNotFoundException());
-		given(resource.getInputStream()).willReturn(StreamUtils.emptyInput());
+		given(resource.getInputStream()).willReturn(InputStream.nullInputStream());
 
 		ResourceScriptSource scriptSource = new ResourceScriptSource(resource);
 		assertThat(scriptSource.isModified()).as("ResourceScriptSource must start off in the 'isModified' state (it obviously isn't).").isTrue();

spring-core/src/main/java/org/springframework/util/StreamUtils.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2022 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -216,11 +216,14 @@ public abstract class StreamUtils {
 		Assert.notNull(in, "No InputStream specified");
 		return (int) in.transferTo(OutputStream.nullOutputStream());
 	}
+
 	/**
 	 * Return an efficient empty {@link InputStream}.
 	 * @return an InputStream which contains no bytes
 	 * @since 4.2.2
+	 * @deprecated as of 6.0 in favor of {@link InputStream#nullInputStream()}
 	 */
+	@Deprecated
 	public static InputStream emptyInput() {
 		return InputStream.nullInputStream();
 	}

spring-core/src/main/java/org/springframework/util/xml/StaxUtils.java

@@ -16,6 +16,7 @@
 
 package org.springframework.util.xml;
 
+import java.io.InputStream;
 import java.util.List;
 import java.util.function.Supplier;
 
@@ -37,7 +38,6 @@ import org.xml.sax.ContentHandler;
 import org.xml.sax.XMLReader;
 
 import org.springframework.lang.Nullable;
-import org.springframework.util.StreamUtils;
 
 /**
  * Convenience methods for working with the StAX API. Partly historic due to JAXP 1.3
@@ -54,7 +54,7 @@ import org.springframework.util.StreamUtils;
 public abstract class StaxUtils {
 
 	private static final XMLResolver NO_OP_XML_RESOLVER =
-			(publicID, systemID, base, ns) -> StreamUtils.emptyInput();
+			(publicID, systemID, base, ns) -> InputStream.nullInputStream();
 
 
 	/**

spring-jdbc/src/main/java/org/springframework/jdbc/support/lob/PassThroughBlob.java

@@ -23,7 +23,6 @@ import java.sql.Blob;
 import java.sql.SQLException;
 
 import org.springframework.lang.Nullable;
-import org.springframework.util.StreamUtils;
 
 /**
  * Simple JDBC {@link Blob} adapter that exposes a given byte array or binary stream.
@@ -65,7 +64,7 @@ class PassThroughBlob implements Blob {
 			return new ByteArrayInputStream(this.content);
 		}
 		else {
-			return (this.binaryStream != null ? this.binaryStream : StreamUtils.emptyInput());
+			return (this.binaryStream != null ? this.binaryStream : InputStream.nullInputStream());
 		}
 	}
 

spring-jdbc/src/main/java/org/springframework/jdbc/support/lob/PassThroughClob.java

@@ -30,7 +30,6 @@ import java.sql.SQLException;
 
 import org.springframework.lang.Nullable;
 import org.springframework.util.FileCopyUtils;
-import org.springframework.util.StreamUtils;
 
 /**
  * Simple JDBC {@link Clob} adapter that exposes a given String or character stream.
@@ -84,7 +83,7 @@ class PassThroughClob implements Clob {
 		}
 		else {
 			return new InputStreamReader(
-					(this.asciiStream != null ? this.asciiStream : StreamUtils.emptyInput()),
+					(this.asciiStream != null ? this.asciiStream : InputStream.nullInputStream()),
 					StandardCharsets.US_ASCII);
 		}
 	}
@@ -100,7 +99,7 @@ class PassThroughClob implements Clob {
 				return new ByteArrayInputStream(tempContent.getBytes(StandardCharsets.US_ASCII));
 			}
 			else {
-				return (this.asciiStream != null ? this.asciiStream : StreamUtils.emptyInput());
+				return (this.asciiStream != null ? this.asciiStream : InputStream.nullInputStream());
 			}
 		}
 		catch (IOException ex) {

spring-test/src/main/java/org/springframework/mock/web/MockHttpServletRequest.java

@@ -69,7 +69,6 @@ import org.springframework.util.LinkedCaseInsensitiveMap;
 import org.springframework.util.LinkedMultiValueMap;
 import org.springframework.util.MultiValueMap;
 import org.springframework.util.ObjectUtils;
-import org.springframework.util.StreamUtils;
 import org.springframework.util.StringUtils;
 import org.springframework.web.util.UrlPathHelper;
 
@@ -102,7 +101,7 @@ public class MockHttpServletRequest implements HttpServletRequest {
 	private static final TimeZone GMT = TimeZone.getTimeZone("GMT");
 
 	private static final ServletInputStream EMPTY_SERVLET_INPUT_STREAM =
-			new DelegatingServletInputStream(StreamUtils.emptyInput());
+			new DelegatingServletInputStream(InputStream.nullInputStream());
 
 	private static final BufferedReader EMPTY_BUFFERED_READER =
 			new BufferedReader(new StringReader(""));

spring-test/src/main/java/org/springframework/test/web/servlet/request/MockHttpServletRequestBuilder.java

@@ -51,7 +51,6 @@ import org.springframework.util.Assert;
 import org.springframework.util.LinkedMultiValueMap;
 import org.springframework.util.MultiValueMap;
 import org.springframework.util.ObjectUtils;
-import org.springframework.util.StreamUtils;
 import org.springframework.util.StringUtils;
 import org.springframework.web.context.WebApplicationContext;
 import org.springframework.web.context.support.WebApplicationContextUtils;
@@ -804,7 +803,7 @@ public class MockHttpServletRequestBuilder
 		HttpInputMessage message = new HttpInputMessage() {
 			@Override
 			public InputStream getBody() {
-				return (content != null ? new ByteArrayInputStream(content) : StreamUtils.emptyInput());
+				return (content != null ? new ByteArrayInputStream(content) : InputStream.nullInputStream());
 			}
 			@Override
 			public HttpHeaders getHeaders() {

spring-web/src/main/java/org/springframework/http/client/HttpComponentsClientHttpResponse.java

@@ -28,7 +28,6 @@ import org.apache.http.util.EntityUtils;
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpStatusCode;
 import org.springframework.lang.Nullable;
-import org.springframework.util.StreamUtils;
 
 /**
  * {@link ClientHttpResponse} implementation based on
@@ -84,7 +83,7 @@ final class HttpComponentsClientHttpResponse implements ClientHttpResponse {
 	@Override
 	public InputStream getBody() throws IOException {
 		HttpEntity entity = this.httpResponse.getEntity();
-		return (entity != null ? entity.getContent() : StreamUtils.emptyInput());
+		return (entity != null ? entity.getContent() : InputStream.nullInputStream());
 	}
 
 	@Override

spring-web/src/main/java/org/springframework/http/client/OkHttp3ClientHttpResponse.java

@@ -26,7 +26,6 @@ import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpStatusCode;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
-import org.springframework.util.StreamUtils;
 
 /**
  * {@link ClientHttpResponse} implementation based on OkHttp 3.x.
@@ -69,7 +68,7 @@ class OkHttp3ClientHttpResponse implements ClientHttpResponse {
 	@Override
 	public InputStream getBody() throws IOException {
 		ResponseBody body = this.response.body();
-		return (body != null ? body.byteStream() : StreamUtils.emptyInput());
+		return (body != null ? body.byteStream() : InputStream.nullInputStream());
 	}
 
 	@Override

spring-web/src/main/java/org/springframework/http/converter/xml/SourceHttpMessageConverter.java

@@ -73,7 +73,7 @@ public class SourceHttpMessageConverter<T extends Source> extends AbstractHttpMe
 			(publicId, systemId) -> new InputSource(new StringReader(""));
 
 	private static final XMLResolver NO_OP_XML_RESOLVER =
-			(publicID, systemID, base, ns) -> StreamUtils.emptyInput();
+			(publicID, systemID, base, ns) -> InputStream.nullInputStream();
 
 	private static final Set<Class<?>> SUPPORTED_CLASSES = new HashSet<>(8);
 

spring-web/src/test/java/org/springframework/web/client/RestTemplateTests.java

@@ -18,6 +18,7 @@ package org.springframework.web.client;
 
 import java.io.ByteArrayInputStream;
 import java.io.IOException;
+import java.io.InputStream;
 import java.net.URI;
 import java.util.Arrays;
 import java.util.Collections;
@@ -52,7 +53,6 @@ import org.springframework.http.converter.GenericHttpMessageConverter;
 import org.springframework.http.converter.HttpMessageConverter;
 import org.springframework.http.converter.json.KotlinSerializationJsonHttpMessageConverter;
 import org.springframework.http.converter.json.MappingJackson2HttpMessageConverter;
-import org.springframework.util.StreamUtils;
 import org.springframework.web.util.DefaultUriBuilderFactory;
 
 import static org.assertj.core.api.Assertions.assertThat;
@@ -284,7 +284,7 @@ class RestTemplateTests {
 		mockSentRequest(GET, "https://example.com/hotels/1/pic/pics%2Flogo.png/size/150x150");
 		mockResponseStatus(HttpStatus.OK);
 		given(response.getHeaders()).willReturn(new HttpHeaders());
-		given(response.getBody()).willReturn(StreamUtils.emptyInput());
+		given(response.getBody()).willReturn(InputStream.nullInputStream());
 
 		Map<String, String> uriVariables = new HashMap<>(2);
 		uriVariables.put("hotel", "1");
@@ -440,7 +440,7 @@ class RestTemplateTests {
 		responseHeaders.setContentType(MediaType.TEXT_PLAIN);
 		responseHeaders.setContentLength(10);
 		given(response.getHeaders()).willReturn(responseHeaders);
-		given(response.getBody()).willReturn(StreamUtils.emptyInput());
+		given(response.getBody()).willReturn(InputStream.nullInputStream());
 		given(converter.read(String.class, response)).willReturn(null);
 
 		String result = template.postForObject("https://example.com", null, String.class);
@@ -460,7 +460,7 @@ class RestTemplateTests {
 		responseHeaders.setContentType(MediaType.TEXT_PLAIN);
 		responseHeaders.setContentLength(10);
 		given(response.getHeaders()).willReturn(responseHeaders);
-		given(response.getBody()).willReturn(StreamUtils.emptyInput());
+		given(response.getBody()).willReturn(InputStream.nullInputStream());
 		given(converter.read(String.class, response)).willReturn(null);
 
 		ResponseEntity<String> result = template.postForEntity("https://example.com", null, String.class);
@@ -556,7 +556,7 @@ class RestTemplateTests {
 		responseHeaders.setContentType(MediaType.TEXT_PLAIN);
 		responseHeaders.setContentLength(10);
 		given(response.getHeaders()).willReturn(responseHeaders);
-		given(response.getBody()).willReturn(StreamUtils.emptyInput());
+		given(response.getBody()).willReturn(InputStream.nullInputStream());
 
 		String result = template.patchForObject("https://example.com", null, String.class);
 		assertThat(result).as("Invalid POST result").isNull();

spring-web/src/test/java/org/springframework/web/filter/ShallowEtagHeaderFilterTests.java

@@ -16,6 +16,7 @@
 
 package org.springframework.web.filter;
 
+import java.io.InputStream;
 import java.nio.charset.StandardCharsets;
 
 import jakarta.servlet.FilterChain;
@@ -23,7 +24,6 @@ import jakarta.servlet.http.HttpServletResponse;
 import org.junit.jupiter.api.Test;
 
 import org.springframework.util.FileCopyUtils;
-import org.springframework.util.StreamUtils;
 import org.springframework.web.testfixture.servlet.MockHttpServletRequest;
 import org.springframework.web.testfixture.servlet.MockHttpServletResponse;
 
@@ -45,18 +45,18 @@ public class ShallowEtagHeaderFilterTests {
 		MockHttpServletRequest request = new MockHttpServletRequest("GET", "/hotels");
 		MockHttpServletResponse response = new MockHttpServletResponse();
 
-		assertThat(filter.isEligibleForEtag(request, response, 200, StreamUtils.emptyInput())).isTrue();
-		assertThat(filter.isEligibleForEtag(request, response, 300, StreamUtils.emptyInput())).isFalse();
+		assertThat(filter.isEligibleForEtag(request, response, 200, InputStream.nullInputStream())).isTrue();
+		assertThat(filter.isEligibleForEtag(request, response, 300, InputStream.nullInputStream())).isFalse();
 
 		request = new MockHttpServletRequest("HEAD", "/hotels");
-		assertThat(filter.isEligibleForEtag(request, response, 200, StreamUtils.emptyInput())).isFalse();
+		assertThat(filter.isEligibleForEtag(request, response, 200, InputStream.nullInputStream())).isFalse();
 
 		request = new MockHttpServletRequest("POST", "/hotels");
-		assertThat(filter.isEligibleForEtag(request, response, 200, StreamUtils.emptyInput())).isFalse();
+		assertThat(filter.isEligibleForEtag(request, response, 200, InputStream.nullInputStream())).isFalse();
 
 		request = new MockHttpServletRequest("POST", "/hotels");
 		request.addHeader("Cache-Control","must-revalidate, no-store");
-		assertThat(filter.isEligibleForEtag(request, response, 200, StreamUtils.emptyInput())).isFalse();
+		assertThat(filter.isEligibleForEtag(request, response, 200, InputStream.nullInputStream())).isFalse();
 	}
 
 	@Test

spring-web/src/testFixtures/java/org/springframework/web/testfixture/servlet/MockHttpServletRequest.java

@@ -69,7 +69,6 @@ import org.springframework.util.LinkedCaseInsensitiveMap;
 import org.springframework.util.LinkedMultiValueMap;
 import org.springframework.util.MultiValueMap;
 import org.springframework.util.ObjectUtils;
-import org.springframework.util.StreamUtils;
 import org.springframework.util.StringUtils;
 import org.springframework.web.util.UrlPathHelper;
 
@@ -102,7 +101,7 @@ public class MockHttpServletRequest implements HttpServletRequest {
 	private static final TimeZone GMT = TimeZone.getTimeZone("GMT");
 
 	private static final ServletInputStream EMPTY_SERVLET_INPUT_STREAM =
-			new DelegatingServletInputStream(StreamUtils.emptyInput());
+			new DelegatingServletInputStream(InputStream.nullInputStream());
 
 	private static final BufferedReader EMPTY_BUFFERED_READER =
 			new BufferedReader(new StringReader(""));

spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/AbstractMessageConverterMethodArgumentResolver.java

@@ -48,7 +48,6 @@ import org.springframework.http.server.ServletServerHttpRequest;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.util.MimeTypeUtils;
-import org.springframework.util.StreamUtils;
 import org.springframework.validation.Errors;
 import org.springframework.validation.annotation.ValidationAnnotationUtils;
 import org.springframework.web.HttpMediaTypeNotSupportedException;
@@ -346,7 +345,7 @@ public abstract class AbstractMessageConverterMethodArgumentResolver implements
 
 		@Override
 		public InputStream getBody() {
-			return (this.body != null ? this.body : StreamUtils.emptyInput());
+			return (this.body != null ? this.body : InputStream.nullInputStream());
 		}
 
 		public boolean hasBody() {