Replace remaining usage of LinkedList with ArrayList/ArrayDeque

Closes gh-25650

spring-beans/src/main/java/org/springframework/beans/factory/parsing/ParseState.java

@@ -16,12 +16,12 @@
 
 package org.springframework.beans.factory.parsing;
 
-import java.util.LinkedList;
+import java.util.ArrayDeque;
 
 import org.springframework.lang.Nullable;
 
 /**
- * Simple {@link LinkedList}-based structure for tracking the logical position during
+ * Simple {@link ArrayDeque}-based structure for tracking the logical position during
  * a parsing process. {@link Entry entries} are added to the LinkedList at
  * each point during the parse phase in a reader-specific manner.
  *
@@ -30,6 +30,7 @@ import org.springframework.lang.Nullable;
  * error messages.
  *
  * @author Rob Harrop
+ * @author Juergen Hoeller
  * @since 2.0
  */
 public final class ParseState {
@@ -40,25 +41,24 @@ public final class ParseState {
 	private static final char TAB = '\t';
 
 	/**
-	 * Internal {@link LinkedList} storage.
+	 * Internal {@link ArrayDeque} storage.
 	 */
-	private final LinkedList<Entry> state;
+	private final ArrayDeque<Entry> state;
 
 
 	/**
 	 * Create a new {@code ParseState} with an empty {@link LinkedList}.
 	 */
 	public ParseState() {
-		this.state = new LinkedList<>();
+		this.state = new ArrayDeque<>();
 	}
 
 	/**
 	 * Create a new {@code ParseState} whose {@link LinkedList} is a {@link Object#clone clone}
 	 * of that of the passed in {@code ParseState}.
 	 */
-	@SuppressWarnings("unchecked")
 	private ParseState(ParseState other) {
-		this.state = (LinkedList<Entry>) other.state.clone();
+		this.state = other.state.clone();
 	}
 
 
@@ -100,15 +100,17 @@ public final class ParseState {
 	@Override
 	public String toString() {
 		StringBuilder sb = new StringBuilder();
-		for (int x = 0; x < this.state.size(); x++) {
-			if (x > 0) {
+		int i = 0;
+		for (ParseState.Entry entry : this.state) {
+			if (i > 0) {
 				sb.append('\n');
-				for (int y = 0; y < x; y++) {
+				for (int j = 0; j < i; j++) {
 					sb.append(TAB);
 				}
 				sb.append("-> ");
 			}
-			sb.append(this.state.get(x));
+			sb.append(entry);
+			i++;
 		}
 		return sb.toString();
 	}
@@ -118,7 +120,6 @@ public final class ParseState {
 	 * Marker interface for entries into the {@link ParseState}.
 	 */
 	public interface Entry {
-
 	}
 
 }

spring-beans/src/main/java/org/springframework/beans/factory/serviceloader/ServiceListFactoryBean.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2020 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.
@@ -16,7 +16,7 @@
 
 package org.springframework.beans.factory.serviceloader;
 
-import java.util.LinkedList;
+import java.util.ArrayList;
 import java.util.List;
 import java.util.ServiceLoader;
 
@@ -35,7 +35,7 @@ public class ServiceListFactoryBean extends AbstractServiceLoaderBasedFactoryBea
 
 	@Override
 	protected Object getObjectToExpose(ServiceLoader<?> serviceLoader) {
-		List<Object> result = new LinkedList<>();
+		List<Object> result = new ArrayList<>();
 		for (Object loaderObject : serviceLoader) {
 			result.add(loaderObject);
 		}

spring-beans/src/main/java/org/springframework/beans/factory/support/ConstructorResolver.java

@@ -24,12 +24,13 @@ import java.lang.reflect.Method;
 import java.lang.reflect.Modifier;
 import java.security.AccessController;
 import java.security.PrivilegedAction;
+import java.util.ArrayDeque;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
+import java.util.Deque;
 import java.util.HashSet;
 import java.util.LinkedHashSet;
-import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
@@ -199,7 +200,7 @@ class ConstructorResolver {
 			AutowireUtils.sortConstructors(candidates);
 			int minTypeDiffWeight = Integer.MAX_VALUE;
 			Set<Constructor<?>> ambiguousConstructors = null;
-			LinkedList<UnsatisfiedDependencyException> causes = null;
+			Deque<UnsatisfiedDependencyException> causes = null;
 
 			for (Constructor<?> candidate : candidates) {
 				int parameterCount = candidate.getParameterCount();
@@ -233,7 +234,7 @@ class ConstructorResolver {
 						}
 						// Swallow and try next constructor.
 						if (causes == null) {
-							causes = new LinkedList<>();
+							causes = new ArrayDeque<>(1);
 						}
 						causes.add(ex);
 						continue;
@@ -511,7 +512,7 @@ class ConstructorResolver {
 				}
 			}
 
-			LinkedList<UnsatisfiedDependencyException> causes = null;
+			Deque<UnsatisfiedDependencyException> causes = null;
 
 			for (Method candidate : candidates) {
 				int parameterCount = candidate.getParameterCount();
@@ -544,7 +545,7 @@ class ConstructorResolver {
 							}
 							// Swallow and try next overloaded factory method.
 							if (causes == null) {
-								causes = new LinkedList<>();
+								causes = new ArrayDeque<>(1);
 							}
 							causes.add(ex);
 							continue;

spring-beans/src/main/java/org/springframework/beans/factory/support/ReplaceOverride.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2020 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.
@@ -17,7 +17,7 @@
 package org.springframework.beans.factory.support;
 
 import java.lang.reflect.Method;
-import java.util.LinkedList;
+import java.util.ArrayList;
 import java.util.List;
 
 import org.springframework.lang.Nullable;
@@ -39,7 +39,7 @@ public class ReplaceOverride extends MethodOverride {
 
 	private final String methodReplacerBeanName;
 
-	private List<String> typeIdentifiers = new LinkedList<>();
+	private final List<String> typeIdentifiers = new ArrayList<>();
 
 
 	/**
@@ -70,6 +70,7 @@ public class ReplaceOverride extends MethodOverride {
 		this.typeIdentifiers.add(identifier);
 	}
 
+
 	@Override
 	public boolean matches(Method method) {
 		if (!method.getName().equals(getMethodName())) {

spring-beans/src/testFixtures/java/org/springframework/beans/testfixture/beans/CollectingReaderEventListener.java

@@ -20,7 +20,6 @@ import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.LinkedHashMap;
-import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
 
@@ -36,13 +35,13 @@ import org.springframework.beans.factory.parsing.ReaderEventListener;
  */
 public class CollectingReaderEventListener implements ReaderEventListener {
 
-	private final List<DefaultsDefinition> defaults = new LinkedList<>();
+	private final List<DefaultsDefinition> defaults = new ArrayList<>();
 
 	private final Map<String, ComponentDefinition> componentDefinitions = new LinkedHashMap<>(8);
 
 	private final Map<String, List<AliasDefinition>> aliasMap = new LinkedHashMap<>(8);
 
-	private final List<ImportDefinition> imports = new LinkedList<>();
+	private final List<ImportDefinition> imports = new ArrayList<>();
 
 
 	@Override

spring-beans/src/testFixtures/java/org/springframework/beans/testfixture/beans/TestBean.java

@@ -22,7 +22,6 @@ import java.util.Collection;
 import java.util.Date;
 import java.util.HashMap;
 import java.util.HashSet;
-import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
 import java.util.Properties;
@@ -77,7 +76,7 @@ public class TestBean implements BeanNameAware, BeanFactoryAware, ITestBean, IOt
 
 	private Float myFloat = Float.valueOf(0.0f);
 
-	private Collection<? super Object> friends = new LinkedList<>();
+	private Collection<? super Object> friends = new ArrayList<>();
 
 	private Set<?> someSet = new HashSet<>();