Remove redundant code

See gh-17875

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/properties/bind/PropertySourcesPlaceholdersResolver.java

@@ -53,7 +53,7 @@ public class PropertySourcesPlaceholdersResolver implements PlaceholdersResolver
 
 	@Override
 	public Object resolvePlaceholders(Object value) {
-		if (value != null && value instanceof String) {
+		if (value instanceof String) {
 			return this.helper.replacePlaceholders((String) value, this::resolvePlaceholder);
 		}
 		return value;

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/env/SpringApplicationJsonEnvironmentPostProcessor.java

@@ -204,7 +204,7 @@ public class SpringApplicationJsonEnvironmentPostProcessor implements Environmen
 		public static JsonPropertyValue get(PropertySource<?> propertySource) {
 			for (String candidate : CANDIDATES) {
 				Object value = propertySource.getProperty(candidate);
-				if (value != null && value instanceof String && StringUtils.hasLength((String) value)) {
+				if (value instanceof String && StringUtils.hasLength((String) value)) {
 					return new JsonPropertyValue(propertySource, candidate, (String) value);
 				}
 			}

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/origin/Origin.java

@@ -44,10 +44,10 @@ public interface Origin {
 			return (Origin) source;
 		}
 		Origin origin = null;
-		if (source != null && source instanceof OriginProvider) {
+		if (source instanceof OriginProvider) {
 			origin = ((OriginProvider) source).getOrigin();
 		}
-		if (origin == null && source != null && source instanceof Throwable) {
+		if (origin == null && source instanceof Throwable) {
 			return from(((Throwable) source).getCause());
 		}
 		return origin;

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/system/ApplicationPid.java

@@ -64,7 +64,7 @@ public class ApplicationPid {
 		if (obj == this) {
 			return true;
 		}
-		if (obj != null && obj instanceof ApplicationPid) {
+		if (obj instanceof ApplicationPid) {
 			return ObjectUtils.nullSafeEquals(this.pid, ((ApplicationPid) obj).pid);
 		}
 		return false;

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/servlet/error/DefaultErrorAttributes.java

@@ -130,7 +130,7 @@ public class DefaultErrorAttributes implements ErrorAttributes, HandlerException
 		Throwable error = getError(webRequest);
 		if (error != null) {
 			while (error instanceof ServletException && error.getCause() != null) {
-				error = ((ServletException) error).getCause();
+				error = error.getCause();
 			}
 			if (this.includeException) {
 				errorAttributes.put("exception", error.getClass().getName());

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/builder/SpringApplicationBuilderTests.java

@@ -155,7 +155,7 @@ public class SpringApplicationBuilderTests {
 		ClassLoader classLoader = new URLClassLoader(new URL[0], getClass().getClassLoader());
 		application.resourceLoader(new DefaultResourceLoader(classLoader));
 		this.context = application.run();
-		assertThat(((SpyApplicationContext) this.context).getClassLoader()).isEqualTo(classLoader);
+		assertThat(this.context.getClassLoader()).isEqualTo(classLoader);
 	}
 
 	@Test

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/context/config/ConfigFileApplicationListenerTests.java

@@ -303,8 +303,8 @@ public class ConfigFileApplicationListenerTests {
 
 	@Test
 	public void defaultPropertyAsFallback() {
-		this.environment.getPropertySources().addLast(
-				new MapPropertySource("defaultProperties", Collections.singletonMap("my.fallback", (Object) "foo")));
+		this.environment.getPropertySources()
+				.addLast(new MapPropertySource("defaultProperties", Collections.singletonMap("my.fallback", "foo")));
 		this.initializer.postProcessEnvironment(this.environment, this.application);
 		String property = this.environment.getProperty("my.fallback");
 		assertThat(property).isEqualTo("foo");
@@ -313,7 +313,7 @@ public class ConfigFileApplicationListenerTests {
 	@Test
 	public void defaultPropertyAsFallbackDuringFileParsing() {
 		this.environment.getPropertySources().addLast(new MapPropertySource("defaultProperties",
-				Collections.singletonMap("spring.config.name", (Object) "testproperties")));
+				Collections.singletonMap("spring.config.name", "testproperties")));
 		this.initializer.postProcessEnvironment(this.environment, this.application);
 		String property = this.environment.getProperty("the.property");
 		assertThat(property).isEqualTo("frompropertiesfile");

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/context/properties/source/ConfigurationPropertyNameTests.java

@@ -409,7 +409,7 @@ public class ConfigurationPropertyNameTests {
 	@Test
 	public void appendWhenElementNameIsNullShouldReturnName() {
 		ConfigurationPropertyName name = ConfigurationPropertyName.of("foo");
-		assertThat((Object) name.append((String) null)).isSameAs(name);
+		assertThat((Object) name.append(null)).isSameAs(name);
 	}
 
 	@Test

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/servlet/server/AbstractServletWebServerFactoryTests.java

@@ -788,8 +788,7 @@ public abstract class AbstractServletWebServerFactoryTests {
 		this.webServer = factory.getWebServer(new ServletRegistrationBean<>(new ExampleServlet(false, true), "/hello"));
 		this.webServer.start();
 		TestGzipInputStreamFactory inputStreamFactory = new TestGzipInputStreamFactory();
-		Map<String, InputStreamFactory> contentDecoderMap = Collections.singletonMap("gzip",
-				(InputStreamFactory) inputStreamFactory);
+		Map<String, InputStreamFactory> contentDecoderMap = Collections.singletonMap("gzip", inputStreamFactory);
 		getResponse(getLocalUrl("/hello"), new HttpComponentsClientHttpRequestFactory(
 				HttpClientBuilder.create().setContentDecoderRegistry(contentDecoderMap).build()));
 		assertThat(inputStreamFactory.wasCompressionUsed()).isTrue();
@@ -993,8 +992,7 @@ public abstract class AbstractServletWebServerFactoryTests {
 			HttpMethod method) throws Exception {
 		String testContent = setUpFactoryForCompression(contentSize, mimeTypes, excludedUserAgents);
 		TestGzipInputStreamFactory inputStreamFactory = new TestGzipInputStreamFactory();
-		Map<String, InputStreamFactory> contentDecoderMap = Collections.singletonMap("gzip",
-				(InputStreamFactory) inputStreamFactory);
+		Map<String, InputStreamFactory> contentDecoderMap = Collections.singletonMap("gzip", inputStreamFactory);
 		String response = getResponse(getLocalUrl("/test.txt"), method,
 				new HttpComponentsClientHttpRequestFactory(HttpClientBuilder.create().setUserAgent("testUserAgent")
 						.setContentDecoderRegistry(contentDecoderMap).build()));