Resolve remaining nullability warnings

Issue: SPR-15869

Author: jhoeller

spring-aop/src/main/java/org/springframework/aop/target/CommonsPool2TargetSource.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2017 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.
@@ -24,6 +24,7 @@
 import org.apache.commons.pool2.impl.GenericObjectPoolConfig;
 
 import org.springframework.lang.Nullable;
+import org.springframework.util.Assert;
 
 /**
  * {@link org.springframework.aop.TargetSource} implementation that holds
@@ -230,6 +231,7 @@ protected ObjectPool createObjectPool() {
 	 */
 	@Override
 	public Object getTarget() throws Exception {
+		Assert.state(this.pool != null, "No Commons ObjectPool available");
 		return this.pool.borrowObject();
 	}
 
@@ -238,17 +240,19 @@ public Object getTarget() throws Exception {
 	 */
 	@Override
 	public void releaseTarget(Object target) throws Exception {
-		this.pool.returnObject(target);
+		if (this.pool != null) {
+			this.pool.returnObject(target);
+		}
 	}
 
 	@Override
 	public int getActiveCount() throws UnsupportedOperationException {
-		return this.pool.getNumActive();
+		return (this.pool != null ? this.pool.getNumActive() : 0);
 	}
 
 	@Override
 	public int getIdleCount() throws UnsupportedOperationException {
-		return this.pool.getNumIdle();
+		return (this.pool != null ? this.pool.getNumIdle() : 0);
 	}
 
 
@@ -257,8 +261,10 @@ public int getIdleCount() throws UnsupportedOperationException {
 	 */
 	@Override
 	public void destroy() throws Exception {
-		logger.debug("Closing Commons ObjectPool");
-		this.pool.close();
+		if (this.pool != null) {
+			logger.debug("Closing Commons ObjectPool");
+			this.pool.close();
+		}
 	}
 
 

spring-jdbc/src/main/java/org/springframework/jdbc/core/JdbcTemplate.java

@@ -446,14 +446,12 @@ public void query(String sql, RowCallbackHandler rch) throws DataAccessException
 
 	@Override
 	public <T> List<T> query(String sql, RowMapper<T> rowMapper) throws DataAccessException {
-		List<T> result = query(sql, new RowMapperResultSetExtractor<>(rowMapper));
-		Assert.state(result != null, "No result list");
-		return result;
+		return nonNull(query(sql, new RowMapperResultSetExtractor<>(rowMapper)));
 	}
 
 	@Override
 	public Map<String, Object> queryForMap(String sql) throws DataAccessException {
-		return queryForObject(sql, getColumnMapRowMapper());
+		return nonNull(queryForObject(sql, getColumnMapRowMapper()));
 	}
 
 	@Override
@@ -481,9 +479,7 @@ public List<Map<String, Object>> queryForList(String sql) throws DataAccessExcep
 
 	@Override
 	public SqlRowSet queryForRowSet(String sql) throws DataAccessException {
-		SqlRowSet result = query(sql, new SqlRowSetResultSetExtractor());
-		Assert.state(result != null, "No SqlRowSet");
-		return result;
+		return nonNull(query(sql, new SqlRowSetResultSetExtractor()));
 	}
 
 	@Override
@@ -798,12 +794,12 @@ public <T> T queryForObject(String sql, Class<T> requiredType, @Nullable Object.
 
 	@Override
 	public Map<String, Object> queryForMap(String sql, Object[] args, int[] argTypes) throws DataAccessException {
-		return queryForObject(sql, args, argTypes, getColumnMapRowMapper());
+		return nonNull(queryForObject(sql, args, argTypes, getColumnMapRowMapper()));
 	}
 
 	@Override
 	public Map<String, Object> queryForMap(String sql, @Nullable Object... args) throws DataAccessException {
-		return queryForObject(sql, args, getColumnMapRowMapper());
+		return nonNull(queryForObject(sql, args, getColumnMapRowMapper()));
 	}
 
 	@Override

spring-jdbc/src/main/java/org/springframework/jdbc/core/namedparam/NamedParameterJdbcTemplate.java

@@ -246,12 +246,16 @@ public <T> T queryForObject(String sql, Map<String, ?> paramMap, Class<T> requir
 
 	@Override
 	public Map<String, Object> queryForMap(String sql, SqlParameterSource paramSource) throws DataAccessException {
-		return queryForObject(sql, paramSource, new ColumnMapRowMapper());
+		Map<String, Object> result = queryForObject(sql, paramSource, new ColumnMapRowMapper());
+		Assert.state(result != null, "No result map");
+		return result;
 	}
 
 	@Override
 	public Map<String, Object> queryForMap(String sql, Map<String, ?> paramMap) throws DataAccessException {
-		return queryForObject(sql, paramMap, new ColumnMapRowMapper());
+		Map<String, Object> result = queryForObject(sql, paramMap, new ColumnMapRowMapper());
+		Assert.state(result != null, "No result map");
+		return result;
 	}
 
 	@Override

spring-jms/src/main/java/org/springframework/jms/listener/adapter/MessageListenerAdapter.java

@@ -216,11 +216,6 @@ public void onMessage(Message message, @Nullable Session session) throws JMSExce
 		// Regular case: find a handler method reflectively.
 		Object convertedMessage = extractMessage(message);
 		String methodName = getListenerMethodName(message, convertedMessage);
-		if (methodName == null) {
-			throw new javax.jms.IllegalStateException("No default listener method specified: " +
-					"Either specify a non-null value for the 'defaultListenerMethod' property or " +
-					"override the 'getListenerMethodName' method.");
-		}
 
 		// Invoke the handler method with appropriate arguments.
 		Object[] listenerArguments = buildListenerArguments(convertedMessage);

spring-jms/src/test/java/org/springframework/jms/listener/adapter/MessageListenerAdapterTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2013 the original author or authors.
+ * Copyright 2002-2017 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.
@@ -19,7 +19,6 @@
 import java.io.ByteArrayInputStream;
 import java.io.Serializable;
 import javax.jms.BytesMessage;
-import javax.jms.IllegalStateException;
 import javax.jms.InvalidDestinationException;
 import javax.jms.JMSException;
 import javax.jms.Message;
@@ -377,40 +376,6 @@ protected Object extractMessage(Message message) {
 		catch (ListenerExecutionFailedException ex) { /* expected */ }
 	}
 
-	@Test
-	public void testFailsIfNoDefaultListenerMethodNameIsSupplied() throws Exception {
-		final TextMessage message = mock(TextMessage.class);
-		given(message.getText()).willReturn(TEXT);
-
-		final MessageListenerAdapter adapter = new MessageListenerAdapter() {
-			@Override
-			protected void handleListenerException(Throwable ex) {
-				assertTrue(ex instanceof IllegalStateException);
-			}
-		};
-		adapter.setDefaultListenerMethod(null);
-		adapter.onMessage(message);
-	}
-
-	@Test
-	public void testFailsWhenOverriddenGetListenerMethodNameReturnsNull() throws Exception {
-		final TextMessage message = mock(TextMessage.class);
-		given(message.getText()).willReturn(TEXT);
-
-		final MessageListenerAdapter adapter = new MessageListenerAdapter() {
-			@Override
-			protected void handleListenerException(Throwable ex) {
-				assertTrue(ex instanceof javax.jms.IllegalStateException);
-			}
-			@Override
-			protected String getListenerMethodName(Message originalMessage, Object extractedMessage) {
-				return null;
-			}
-		};
-		adapter.setDefaultListenerMethod(null);
-		adapter.onMessage(message);
-	}
-
 	@Test
 	public void testWithResponsiveMessageDelegateWhenReturnTypeIsNotAJMSMessageAndNoMessageConverterIsSupplied() throws Exception {
 		final TextMessage sentTextMessage = mock(TextMessage.class);

spring-web/src/main/java/org/springframework/http/MediaType.java

@@ -525,7 +525,7 @@ public static MediaType parseMediaType(String mediaType) {
 	 * @return the list of media types
 	 * @throws InvalidMediaTypeException if the media type value cannot be parsed
 	 */
-	public static List<MediaType> parseMediaTypes(String mediaTypes) {
+	public static List<MediaType> parseMediaTypes(@Nullable String mediaTypes) {
 		if (!StringUtils.hasLength(mediaTypes)) {
 			return Collections.emptyList();
 		}

spring-webflux/src/main/java/org/springframework/web/reactive/result/condition/AbstractNameValueExpression.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2017 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.
@@ -17,6 +17,7 @@
 package org.springframework.web.reactive.result.condition;
 
 import org.springframework.lang.Nullable;
+import org.springframework.util.ObjectUtils;
 import org.springframework.web.server.ServerWebExchange;
 
 /**
@@ -36,20 +37,22 @@ abstract class AbstractNameValueExpression<T> implements NameValueExpression<T>
 
 	protected final boolean isNegated;
 
+
 	AbstractNameValueExpression(String expression) {
 		int separator = expression.indexOf('=');
 		if (separator == -1) {
 			this.isNegated = expression.startsWith("!");
-			this.name = isNegated ? expression.substring(1) : expression;
+			this.name = (this.isNegated ? expression.substring(1) : expression);
 			this.value = null;
 		}
 		else {
 			this.isNegated = (separator > 0) && (expression.charAt(separator - 1) == '!');
-			this.name = isNegated ? expression.substring(0, separator - 1) : expression.substring(0, separator);
+			this.name = (this.isNegated ? expression.substring(0, separator - 1) : expression.substring(0, separator));
 			this.value = parseValue(expression.substring(separator + 1));
 		}
 	}
 
+
 	@Override
 	public String getName() {
 		return this.name;
@@ -66,10 +69,6 @@ public boolean isNegated() {
 		return this.isNegated;
 	}
 
-	protected abstract boolean isCaseSensitiveName();
-
-	protected abstract T parseValue(String valueExpression);
-
 	public final boolean match(ServerWebExchange exchange) {
 		boolean isMatch;
 		if (this.value != null) {
@@ -81,10 +80,16 @@ public final boolean match(ServerWebExchange exchange) {
 		return this.isNegated != isMatch;
 	}
 
+
+	protected abstract boolean isCaseSensitiveName();
+
+	protected abstract T parseValue(String valueExpression);
+
 	protected abstract boolean matchName(ServerWebExchange exchange);
 
 	protected abstract boolean matchValue(ServerWebExchange exchange);
 
+
 	@Override
 	public boolean equals(Object obj) {
 		if (this == obj) {
@@ -103,28 +108,28 @@ public boolean equals(Object obj) {
 
 	@Override
 	public int hashCode() {
-		int result = isCaseSensitiveName() ? name.hashCode() : name.toLowerCase().hashCode();
-		result = 31 * result + (value != null ? value.hashCode() : 0);
-		result = 31 * result + (isNegated ? 1 : 0);
+		int result = (isCaseSensitiveName() ? this.name : this.name.toLowerCase()).hashCode();
+		result = 31 * result + ObjectUtils.nullSafeHashCode(this.value);
+		result = 31 * result + (this.isNegated ? 1 : 0);
 		return result;
 	}
 
 	@Override
 	public String toString() {
 		StringBuilder builder = new StringBuilder();
-		if (value != null) {
-			builder.append(name);
-			if (isNegated) {
+		if (this.value != null) {
+			builder.append(this.name);
+			if (this.isNegated) {
 				builder.append('!');
 			}
 			builder.append('=');
-			builder.append(value);
+			builder.append(this.value);
 		}
 		else {
-			if (isNegated) {
+			if (this.isNegated) {
 				builder.append('!');
 			}
-			builder.append(name);
+			builder.append(this.name);
 		}
 		return builder.toString();
 	}

spring-webflux/src/main/java/org/springframework/web/reactive/result/condition/HeadersRequestCondition.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2017 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.
@@ -159,12 +159,12 @@ protected String parseValue(String valueExpression) {
 
 		@Override
 		protected boolean matchName(ServerWebExchange exchange) {
-			return exchange.getRequest().getHeaders().get(name) != null;
+			return (exchange.getRequest().getHeaders().get(this.name) != null);
 		}
 
 		@Override
 		protected boolean matchValue(ServerWebExchange exchange) {
-			return value.equals(exchange.getRequest().getHeaders().getFirst(name));
+			return (this.value != null && this.value.equals(exchange.getRequest().getHeaders().getFirst(this.name)));
 		}
 	}
 

spring-webflux/src/main/java/org/springframework/web/reactive/result/condition/ParamsRequestCondition.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2017 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.
@@ -146,7 +146,8 @@ protected boolean matchName(ServerWebExchange exchange) {
 
 		@Override
 		protected boolean matchValue(ServerWebExchange exchange) {
-			return this.value.equals(exchange.getRequest().getQueryParams().getFirst(this.name));
+			return (this.value != null &&
+					this.value.equals(exchange.getRequest().getQueryParams().getFirst(this.name)));
 		}
 	}
 

spring-webflux/src/main/java/org/springframework/web/reactive/result/view/DefaultRendering.java

@@ -54,6 +54,7 @@ class DefaultRendering implements Rendering {
 
 
 	@Override
+	@Nullable
 	public Object view() {
 		return this.view;
 	}