Reduce JarURLConnection allocations

Update JarURLConnection & Handler so that a shared static final
connection is returned for entries that cannot be found.

See gh-6215

spring-boot-tools/spring-boot-loader/src/main/java/org/springframework/boot/loader/jar/CentralDirectoryFileHeader.java

@@ -65,7 +65,7 @@ final class CentralDirectoryFileHeader implements FileHeader {
 	}
 
 	void load(byte[] data, int dataOffset, RandomAccessData variableData,
-			int variableOffset) throws IOException {
+			int variableOffset, JarEntryFilter filter) throws IOException {
 		// Load fixed part
 		this.header = data;
 		this.headerOffset = dataOffset;
@@ -81,6 +81,9 @@ final class CentralDirectoryFileHeader implements FileHeader {
 			dataOffset = 0;
 		}
 		this.name = new AsciiBytes(data, dataOffset, (int) nameLength);
+		if (filter != null) {
+			this.name = filter.apply(this.name);
+		}
 		this.extra = NO_EXTRA;
 		this.comment = NO_COMMENT;
 		if (extraLength > 0) {
@@ -172,10 +175,10 @@ final class CentralDirectoryFileHeader implements FileHeader {
 	}
 
 	public static CentralDirectoryFileHeader fromRandomAccessData(RandomAccessData data,
-			int offset) throws IOException {
+			int offset, JarEntryFilter filter) throws IOException {
 		CentralDirectoryFileHeader fileHeader = new CentralDirectoryFileHeader();
 		byte[] bytes = Bytes.get(data.getSubsection(offset, 46));
-		fileHeader.load(bytes, 0, data, offset);
+		fileHeader.load(bytes, 0, data, offset, filter);
 		return fileHeader;
 	}
 

spring-boot-tools/spring-boot-loader/src/main/java/org/springframework/boot/loader/jar/CentralDirectoryParser.java

@@ -65,7 +65,7 @@ class CentralDirectoryParser {
 		CentralDirectoryFileHeader fileHeader = new CentralDirectoryFileHeader();
 		int dataOffset = 0;
 		for (int i = 0; i < endRecord.getNumberOfRecords(); i++) {
-			fileHeader.load(bytes, dataOffset, null, 0);
+			fileHeader.load(bytes, dataOffset, null, 0, null);
 			visitFileHeader(dataOffset, fileHeader);
 			dataOffset += this.CENTRAL_DIRECTORY_HEADER_BASE_SIZE
 					+ fileHeader.getName().length() + fileHeader.getComment().length()

spring-boot-tools/spring-boot-loader/src/main/java/org/springframework/boot/loader/jar/Handler.java

 /*
- * Copyright 2012-2015 the original author or authors.
+ * Copyright 2012-2016 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.
@@ -85,10 +85,10 @@ public class Handler extends URLStreamHandler {
 	@Override
 	protected URLConnection openConnection(URL url) throws IOException {
 		if (this.jarFile != null) {
-			return new JarURLConnection(url, this.jarFile);
+			return JarURLConnection.get(url, this.jarFile);
 		}
 		try {
-			return new JarURLConnection(url, getRootJarFileFromUrl(url));
+			return JarURLConnection.get(url, getRootJarFileFromUrl(url));
 		}
 		catch (Exception ex) {
 			return openFallbackConnection(url, ex);

spring-boot-tools/spring-boot-loader/src/main/java/org/springframework/boot/loader/jar/JarEntry.java

@@ -39,8 +39,8 @@ class JarEntry extends java.util.jar.JarEntry implements FileHeader {
 
 	private long localHeaderOffset;
 
-	JarEntry(JarFile jarFile, String name, CentralDirectoryFileHeader header) {
-		super(name);
+	JarEntry(JarFile jarFile, CentralDirectoryFileHeader header) {
+		super(header.getName().toString());
 		this.jarFile = jarFile;
 		this.localHeaderOffset = header.getLocalHeaderOffset();
 		setCompressedSize(header.getCompressedSize());

spring-boot-tools/spring-boot-loader/src/main/java/org/springframework/boot/loader/jar/JarFile.java

@@ -200,6 +200,10 @@ public class JarFile extends java.util.jar.JarFile {
 		return (JarEntry) getEntry(name);
 	}
 
+	public boolean containsEntry(String name) {
+		return this.entries.containsEntry(name);
+	}
+
 	@Override
 	public ZipEntry getEntry(String name) {
 		return this.entries.getEntry(name);
@@ -320,8 +324,7 @@ public class JarFile extends java.util.jar.JarFile {
 
 	@Override
 	public String getName() {
-		String path = this.pathFromRoot;
-		return this.rootFile.getFile() + path;
+		return this.rootFile.getFile() + this.pathFromRoot;
 	}
 
 	boolean isSigned() {

spring-boot-tools/spring-boot-loader/src/main/java/org/springframework/boot/loader/jar/JarFileEntries.java

@@ -66,11 +66,12 @@ class JarFileEntries implements CentralDirectoryVisitor, Iterable<JarEntry> {
 
 	private int[] positions;
 
-	private final Map<Integer, JarEntry> entriesCache = Collections
-			.synchronizedMap(new LinkedHashMap<Integer, JarEntry>(16, 0.75f, true) {
+	private final Map<Integer, FileHeader> entriesCache = Collections
+			.synchronizedMap(new LinkedHashMap<Integer, FileHeader>(16, 0.75f, true) {
 
 				@Override
-				protected boolean removeEldestEntry(Map.Entry<Integer, JarEntry> eldest) {
+				protected boolean removeEldestEntry(
+						Map.Entry<Integer, FileHeader> eldest) {
 					if (JarFileEntries.this.jarFile.isSigned()) {
 						return false;
 					}
@@ -165,6 +166,10 @@ class JarFileEntries implements CentralDirectoryVisitor, Iterable<JarEntry> {
 		return new EntryIterator();
 	}
 
+	public boolean containsEntry(String name) {
+		return getEntry(name, FileHeader.class, true) != null;
+	}
+
 	public JarEntry getEntry(String name) {
 		return getEntry(name, JarEntry.class, true);
 	}
@@ -235,21 +240,17 @@ class JarFileEntries implements CentralDirectoryVisitor, Iterable<JarEntry> {
 	@SuppressWarnings("unchecked")
 	private <T extends FileHeader> T getEntry(int index, Class<T> type,
 			boolean cacheEntry) {
-		JarEntry entry = this.entriesCache.get(index);
-		if (entry != null) {
-			return (T) entry;
-		}
 		try {
-			CentralDirectoryFileHeader header = CentralDirectoryFileHeader
-					.fromRandomAccessData(this.centralDirectoryData,
-							this.centralDirectoryOffsets[index]);
-			if (FileHeader.class.equals(type)) {
-				// No need to convert
-				return (T) header;
+			FileHeader cached = this.entriesCache.get(index);
+			FileHeader entry = (cached != null ? cached
+					: CentralDirectoryFileHeader.fromRandomAccessData(
+							this.centralDirectoryData,
+							this.centralDirectoryOffsets[index], this.filter));
+			if (CentralDirectoryFileHeader.class.equals(entry.getClass())
+					&& type.equals(JarEntry.class)) {
+				entry = new JarEntry(this.jarFile, (CentralDirectoryFileHeader) entry);
 			}
-			entry = new JarEntry(this.jarFile, applyFilter(header.getName()).toString(),
-					header);
-			if (cacheEntry) {
+			if (cacheEntry && cached != entry) {
 				this.entriesCache.put(index, entry);
 			}
 			return (T) entry;

spring-boot-tools/spring-boot-loader/src/main/java/org/springframework/boot/loader/jar/JarURLConnection.java

@@ -35,9 +35,15 @@ import java.security.Permission;
  * @author Phillip Webb
  * @author Andy Wilkinson
  */
-class JarURLConnection extends java.net.JarURLConnection {
+final class JarURLConnection extends java.net.JarURLConnection {
 
-	private static final FileNotFoundException FILE_NOT_FOUND_EXCEPTION = new FileNotFoundException();
+	private static ThreadLocal<Boolean> useFastExceptions = new ThreadLocal<Boolean>();
+
+	private static final FileNotFoundException FILE_NOT_FOUND_EXCEPTION = new FileNotFoundException(
+			"Jar file or entry not found");
+
+	private static final IllegalStateException NOT_FOUND_CONNECTION_EXCEPTION = new IllegalStateException(
+			FILE_NOT_FOUND_EXCEPTION);
 
 	private static final String SEPARATOR = "!/";
 
@@ -63,7 +69,8 @@ class JarURLConnection extends java.net.JarURLConnection {
 
 	private static final String READ_ACTION = "read";
 
-	private static ThreadLocal<Boolean> useFastExceptions = new ThreadLocal<Boolean>();
+	private static final JarURLConnection NOT_FOUND_CONNECTION = JarURLConnection
+			.notFound();
 
 	private final JarFile jarFile;
 
@@ -75,48 +82,20 @@ class JarURLConnection extends java.net.JarURLConnection {
 
 	private JarEntry jarEntry;
 
-	protected JarURLConnection(URL url, JarFile jarFile) throws IOException {
+	private JarURLConnection(URL url, JarFile jarFile, JarEntryName jarEntryName)
+			throws IOException {
 		// What we pass to super is ultimately ignored
 		super(EMPTY_JAR_URL);
 		this.url = url;
-		String spec = extractFullSpec(url, jarFile.getPathFromRoot());
-		int separator;
-		int index = 0;
-		while ((separator = spec.indexOf(SEPARATOR, index)) > 0) {
-			jarFile = getNestedJarFile(jarFile, spec.substring(index, separator));
-			index += separator + SEPARATOR.length();
-		}
 		this.jarFile = jarFile;
-		this.jarEntryName = getJarEntryName(spec.substring(index));
-	}
-
-	private String extractFullSpec(URL url, String pathFromRoot) {
-		String file = url.getFile();
-		int separatorIndex = file.indexOf(SEPARATOR);
-		if (separatorIndex < 0) {
-			return "";
-		}
-		int specIndex = separatorIndex + SEPARATOR.length() + pathFromRoot.length();
-		return file.substring(specIndex);
-	}
-
-	private JarFile getNestedJarFile(JarFile jarFile, String name) throws IOException {
-		JarEntry jarEntry = jarFile.getJarEntry(name);
-		if (jarEntry == null) {
-			throwFileNotFound(jarEntry, jarFile);
-		}
-		return jarFile.getNestedJarFile(jarEntry);
-	}
-
-	private JarEntryName getJarEntryName(String spec) {
-		if (spec.length() == 0) {
-			return EMPTY_JAR_ENTRY_NAME;
-		}
-		return new JarEntryName(spec);
+		this.jarEntryName = jarEntryName;
 	}
 
 	@Override
 	public void connect() throws IOException {
+		if (this.jarFile == null) {
+			throw FILE_NOT_FOUND_EXCEPTION;
+		}
 		if (!this.jarEntryName.isEmpty() && this.jarEntry == null) {
 			this.jarEntry = this.jarFile.getJarEntry(getEntryName());
 			if (this.jarEntry == null) {
@@ -126,15 +105,6 @@ class JarURLConnection extends java.net.JarURLConnection {
 		this.connected = true;
 	}
 
-	private void throwFileNotFound(Object entry, JarFile jarFile)
-			throws FileNotFoundException {
-		if (Boolean.TRUE.equals(useFastExceptions.get())) {
-			throw FILE_NOT_FOUND_EXCEPTION;
-		}
-		throw new FileNotFoundException(
-				"JAR entry " + entry + " not found in " + jarFile.getName());
-	}
-
 	@Override
 	public JarFile getJarFile() throws IOException {
 		connect();
@@ -143,6 +113,9 @@ class JarURLConnection extends java.net.JarURLConnection {
 
 	@Override
 	public URL getJarFileURL() {
+		if (this.jarFile == null) {
+			throw NOT_FOUND_CONNECTION_EXCEPTION;
+		}
 		if (this.jarFileUrl == null) {
 			this.jarFileUrl = buildJarFileUrl();
 		}
@@ -167,7 +140,7 @@ class JarURLConnection extends java.net.JarURLConnection {
 
 	@Override
 	public JarEntry getJarEntry() throws IOException {
-		if (this.jarEntryName.isEmpty()) {
+		if (this.jarEntryName == null || this.jarEntryName.isEmpty()) {
 			return null;
 		}
 		connect();
@@ -176,11 +149,17 @@ class JarURLConnection extends java.net.JarURLConnection {
 
 	@Override
 	public String getEntryName() {
+		if (this.jarFile == null) {
+			throw NOT_FOUND_CONNECTION_EXCEPTION;
+		}
 		return this.jarEntryName.toString();
 	}
 
 	@Override
 	public InputStream getInputStream() throws IOException {
+		if (this.jarFile == null) {
+			throw FILE_NOT_FOUND_EXCEPTION;
+		}
 		if (this.jarEntryName.isEmpty()) {
 			throw new IOException("no entry name specified");
 		}
@@ -192,8 +171,20 @@ class JarURLConnection extends java.net.JarURLConnection {
 		return inputStream;
 	}
 
+	private void throwFileNotFound(Object entry, JarFile jarFile)
+			throws FileNotFoundException {
+		if (Boolean.TRUE.equals(useFastExceptions.get())) {
+			throw FILE_NOT_FOUND_EXCEPTION;
+		}
+		throw new FileNotFoundException(
+				"JAR entry " + entry + " not found in " + jarFile.getName());
+	}
+
 	@Override
 	public int getContentLength() {
+		if (this.jarFile == null) {
+			return -1;
+		}
 		try {
 			if (this.jarEntryName.isEmpty()) {
 				return this.jarFile.size();
@@ -214,11 +205,14 @@ class JarURLConnection extends java.net.JarURLConnection {
 
 	@Override
 	public String getContentType() {
-		return this.jarEntryName.getContentType();
+		return (this.jarEntryName == null ? null : this.jarEntryName.getContentType());
 	}
 
 	@Override
 	public Permission getPermission() throws IOException {
+		if (this.jarFile == null) {
+			throw FILE_NOT_FOUND_EXCEPTION;
+		}
 		if (this.permission == null) {
 			this.permission = new FilePermission(
 					this.jarFile.getRootJarFile().getFile().getPath(), READ_ACTION);
@@ -230,6 +224,56 @@ class JarURLConnection extends java.net.JarURLConnection {
 		JarURLConnection.useFastExceptions.set(useFastExceptions);
 	}
 
+	static JarURLConnection get(URL url, JarFile jarFile) throws IOException {
+		String spec = extractFullSpec(url, jarFile.getPathFromRoot());
+		int separator;
+		int index = 0;
+		while ((separator = spec.indexOf(SEPARATOR, index)) > 0) {
+			String entryName = spec.substring(index, separator);
+			JarEntry jarEntry = jarFile.getJarEntry(entryName);
+			if (jarEntry == null) {
+				return JarURLConnection.notFound(jarFile, JarEntryName.get(entryName));
+			}
+			jarFile = jarFile.getNestedJarFile(jarEntry);
+			index += separator + SEPARATOR.length();
+		}
+		JarEntryName jarEntryName = JarEntryName.get(spec, index);
+		if (Boolean.TRUE.equals(useFastExceptions.get())) {
+			if (!jarEntryName.isEmpty()
+					&& !jarFile.containsEntry(jarEntryName.toString())) {
+				return NOT_FOUND_CONNECTION;
+			}
+		}
+		return new JarURLConnection(url, jarFile, jarEntryName);
+	}
+
+	private static String extractFullSpec(URL url, String pathFromRoot) {
+		String file = url.getFile();
+		int separatorIndex = file.indexOf(SEPARATOR);
+		if (separatorIndex < 0) {
+			return "";
+		}
+		int specIndex = separatorIndex + SEPARATOR.length() + pathFromRoot.length();
+		return file.substring(specIndex);
+	}
+
+	private static JarURLConnection notFound() {
+		try {
+			return notFound(null, null);
+		}
+		catch (IOException ex) {
+			throw new IllegalStateException(ex);
+		}
+	}
+
+	private static JarURLConnection notFound(JarFile jarFile, JarEntryName jarEntryName)
+			throws IOException {
+		if (Boolean.TRUE.equals(useFastExceptions.get())) {
+			return NOT_FOUND_CONNECTION;
+		}
+		return new JarURLConnection(null, jarFile, jarEntryName);
+	}
+
 	/**
 	 * A JarEntryName parsed from a URL String.
 	 */
@@ -316,6 +360,17 @@ class JarURLConnection extends java.net.JarURLConnection {
 			return type;
 		}
 
+		public static JarEntryName get(String spec) {
+			return get(spec, 0);
+		}
+
+		public static JarEntryName get(String spec, int beginIndex) {
+			if (spec.length() <= beginIndex) {
+				return EMPTY_JAR_ENTRY_NAME;
+			}
+			return new JarEntryName(spec.substring(beginIndex));
+		}
+
 	}
 
 }

spring-boot-tools/spring-boot-loader/src/test/java/org/springframework/boot/loader/jar/JarURLConnectionTests.java

@@ -18,11 +18,13 @@ package org.springframework.boot.loader.jar;
 
 import java.io.ByteArrayInputStream;
 import java.io.File;
+import java.io.FileNotFoundException;
 import java.net.URL;
 
 import org.junit.Before;
 import org.junit.Rule;
 import org.junit.Test;
+import org.junit.rules.ExpectedException;
 import org.junit.rules.TemporaryFolder;
 
 import org.springframework.boot.loader.TestJarCreator;
@@ -33,12 +35,16 @@ import static org.assertj.core.api.Assertions.assertThat;
  * Tests for {@link JarURLConnection}.
  *
  * @author Andy Wilkinson
+ * @author Phillip Webb
  */
 public class JarURLConnectionTests {
 
 	@Rule
 	public TemporaryFolder temporaryFolder = new TemporaryFolder(new File("target"));
 
+	@Rule
+	public ExpectedException thrown = ExpectedException.none();
+
 	private File rootJarFile;
 
 	private JarFile jarFile;
@@ -52,76 +58,84 @@ public class JarURLConnectionTests {
 
 	@Test
 	public void connectionToRootUsingAbsoluteUrl() throws Exception {
-		URL absoluteUrl = new URL("jar:file:" + getAbsolutePath() + "!/");
-		assertThat(new JarURLConnection(absoluteUrl, this.jarFile).getContent())
+		URL url = new URL("jar:file:" + getAbsolutePath() + "!/");
+		assertThat(JarURLConnection.get(url, this.jarFile).getContent())
 				.isSameAs(this.jarFile);
 	}
 
 	@Test
 	public void connectionToRootUsingRelativeUrl() throws Exception {
-		URL relativeUrl = new URL("jar:file:" + getRelativePath() + "!/");
-		assertThat(new JarURLConnection(relativeUrl, this.jarFile).getContent())
+		URL url = new URL("jar:file:" + getRelativePath() + "!/");
+		assertThat(JarURLConnection.get(url, this.jarFile).getContent())
 				.isSameAs(this.jarFile);
 	}
 
 	@Test
 	public void connectionToEntryUsingAbsoluteUrl() throws Exception {
-		URL absoluteUrl = new URL("jar:file:" + getAbsolutePath() + "!/1.dat");
-		assertThat(new JarURLConnection(absoluteUrl, this.jarFile).getInputStream())
+		URL url = new URL("jar:file:" + getAbsolutePath() + "!/1.dat");
+		assertThat(JarURLConnection.get(url, this.jarFile).getInputStream())
 				.hasSameContentAs(new ByteArrayInputStream(new byte[] { 1 }));
 	}
 
 	@Test
 	public void connectionToEntryUsingRelativeUrl() throws Exception {
-		URL relativeUrl = new URL("jar:file:" + getRelativePath() + "!/1.dat");
-		assertThat(new JarURLConnection(relativeUrl, this.jarFile).getInputStream())
+		URL url = new URL("jar:file:" + getRelativePath() + "!/1.dat");
+		assertThat(JarURLConnection.get(url, this.jarFile).getInputStream())
 				.hasSameContentAs(new ByteArrayInputStream(new byte[] { 1 }));
 	}
 
 	@Test
 	public void connectionToEntryUsingAbsoluteUrlWithFileColonSlashSlashPrefix()
 			throws Exception {
-		URL absoluteUrl = new URL("jar:file:/" + getAbsolutePath() + "!/1.dat");
-		assertThat(new JarURLConnection(absoluteUrl, this.jarFile).getInputStream())
+		URL url = new URL("jar:file:/" + getAbsolutePath() + "!/1.dat");
+		assertThat(JarURLConnection.get(url, this.jarFile).getInputStream())
 				.hasSameContentAs(new ByteArrayInputStream(new byte[] { 1 }));
 	}
 
 	@Test
 	public void connectionToEntryUsingAbsoluteUrlForNestedEntry() throws Exception {
-		URL absoluteUrl = new URL(
-				"jar:file:" + getAbsolutePath() + "!/nested.jar!/3.dat");
-		assertThat(new JarURLConnection(absoluteUrl, this.jarFile).getInputStream())
+		URL url = new URL("jar:file:" + getAbsolutePath() + "!/nested.jar!/3.dat");
+		assertThat(JarURLConnection.get(url, this.jarFile).getInputStream())
 				.hasSameContentAs(new ByteArrayInputStream(new byte[] { 3 }));
 	}
 
 	@Test
 	public void connectionToEntryUsingRelativeUrlForNestedEntry() throws Exception {
-		URL relativeUrl = new URL(
-				"jar:file:" + getRelativePath() + "!/nested.jar!/3.dat");
-		assertThat(new JarURLConnection(relativeUrl, this.jarFile).getInputStream())
+		URL url = new URL("jar:file:" + getRelativePath() + "!/nested.jar!/3.dat");
+		assertThat(JarURLConnection.get(url, this.jarFile).getInputStream())
 				.hasSameContentAs(new ByteArrayInputStream(new byte[] { 3 }));
 	}
 
 	@Test
 	public void connectionToEntryUsingAbsoluteUrlForEntryFromNestedJarFile()
 			throws Exception {
-		URL absoluteUrl = new URL(
-				"jar:file:" + getAbsolutePath() + "!/nested.jar!/3.dat");
-		assertThat(new JarURLConnection(absoluteUrl,
-				this.jarFile.getNestedJarFile(this.jarFile.getEntry("nested.jar")))
-						.getInputStream()).hasSameContentAs(
-								new ByteArrayInputStream(new byte[] { 3 }));
+		URL url = new URL("jar:file:" + getAbsolutePath() + "!/nested.jar!/3.dat");
+		JarFile nested = this.jarFile
+				.getNestedJarFile(this.jarFile.getEntry("nested.jar"));
+		assertThat(JarURLConnection.get(url, nested).getInputStream())
+				.hasSameContentAs(new ByteArrayInputStream(new byte[] { 3 }));
 	}
 
 	@Test
 	public void connectionToEntryUsingRelativeUrlForEntryFromNestedJarFile()
 			throws Exception {
-		URL absoluteUrl = new URL(
-				"jar:file:" + getRelativePath() + "!/nested.jar!/3.dat");
-		assertThat(new JarURLConnection(absoluteUrl,
-				this.jarFile.getNestedJarFile(this.jarFile.getEntry("nested.jar")))
-						.getInputStream()).hasSameContentAs(
-								new ByteArrayInputStream(new byte[] { 3 }));
+		URL url = new URL("jar:file:" + getRelativePath() + "!/nested.jar!/3.dat");
+		JarFile nested = this.jarFile
+				.getNestedJarFile(this.jarFile.getEntry("nested.jar"));
+		assertThat(JarURLConnection.get(url, nested).getInputStream())
+				.hasSameContentAs(new ByteArrayInputStream(new byte[] { 3 }));
+	}
+
+	@Test
+	public void nestedJarNotFound() throws Exception {
+		URL url = new URL(
+				"jar:file:" + getAbsolutePath() + "!/nested.jar!/missing.jar!/1.dat");
+		JarFile nested = this.jarFile
+				.getNestedJarFile(this.jarFile.getEntry("nested.jar"));
+		JarURLConnection connection = JarURLConnection.get(url, nested);
+		this.thrown.expect(FileNotFoundException.class);
+		this.thrown.expectMessage("JAR entry missing.jar not found in");
+		connection.connect();
 	}
 
 	private String getAbsolutePath() {