8145680: Remove unnecessary explicit initialization of volatile variables in java.base

Reviewed-by: alanb, chegar, jfranck, shade

jdk/src/java.base/linux/classes/sun/nio/ch/EPollSelectorImpl.java

@@ -29,7 +29,6 @@ import java.io.IOException;
 import java.nio.channels.*;
 import java.nio.channels.spi.*;
 import java.util.*;
-import sun.misc.*;
 
 /**
  * An implementation of Selector for Linux 2.6+ kernels that uses
@@ -50,7 +49,7 @@ class EPollSelectorImpl
     private Map<Integer,SelectionKeyImpl> fdToKey;
 
     // True if this Selector has been closed
-    private volatile boolean closed = false;
+    private volatile boolean closed;
 
     // Lock for interrupt triggering and clearing
     private final Object interruptLock = new Object();

jdk/src/java.base/share/classes/com/sun/crypto/provider/SunJCE.java

@@ -93,7 +93,7 @@ public final class SunJCE extends Provider {
 
     // Instance of this provider, so we don't have to call the provider list
     // to find ourselves or run the risk of not being in the list.
-    private static volatile SunJCE instance = null;
+    private static volatile SunJCE instance;
 
     // lazy initialize SecureRandom to avoid potential recursion if Sun
     // provider has not been installed yet

jdk/src/java.base/share/classes/java/io/PipedInputStream.java

@@ -48,9 +48,9 @@ package java.io;
  * @since   1.0
  */
 public class PipedInputStream extends InputStream {
-    boolean closedByWriter = false;
-    volatile boolean closedByReader = false;
-    boolean connected = false;
+    boolean closedByWriter;
+    volatile boolean closedByReader;
+    boolean connected;
 
         /* REMIND: identification of the read and write sides needs to be
            more sophisticated.  Either using thread groups (but what about

jdk/src/java.base/share/classes/java/lang/Class.java

@@ -2518,7 +2518,7 @@ public final class Class<T> implements java.io.Serializable,
 
     // Incremented by the VM on each call to JVM TI RedefineClasses()
     // that redefines this class or a superclass.
-    private transient volatile int classRedefinedCount = 0;
+    private transient volatile int classRedefinedCount;
 
     // Lazily create and cache ReflectionData
     private ReflectionData<T> reflectionData() {
@@ -3331,7 +3331,8 @@ public final class Class<T> implements java.io.Serializable,
      * uncloned, cached, and shared by all callers.
      */
     T[] getEnumConstantsShared() {
-        if (enumConstants == null) {
+        T[] constants = enumConstants;
+        if (constants == null) {
             if (!isEnum()) return null;
             try {
                 final Method values = getMethod("values");
@@ -3344,16 +3345,16 @@ public final class Class<T> implements java.io.Serializable,
                         });
                 @SuppressWarnings("unchecked")
                 T[] temporaryConstants = (T[])values.invoke(null);
-                enumConstants = temporaryConstants;
+                enumConstants = constants = temporaryConstants;
             }
             // These can happen when users concoct enum-like classes
             // that don't comply with the enum spec.
             catch (InvocationTargetException | NoSuchMethodException |
                    IllegalAccessException ex) { return null; }
         }
-        return enumConstants;
+        return constants;
     }
-    private transient volatile T[] enumConstants = null;
+    private transient volatile T[] enumConstants;
 
     /**
      * Returns a map from simple name to enum constant.  This package-private
@@ -3363,19 +3364,21 @@ public final class Class<T> implements java.io.Serializable,
      * created lazily on first use.  Typically it won't ever get created.
      */
     Map<String, T> enumConstantDirectory() {
-        if (enumConstantDirectory == null) {
+        Map<String, T> directory = enumConstantDirectory;
+        if (directory == null) {
             T[] universe = getEnumConstantsShared();
             if (universe == null)
                 throw new IllegalArgumentException(
                     getName() + " is not an enum type");
-            Map<String, T> m = new HashMap<>(2 * universe.length);
-            for (T constant : universe)
-                m.put(((Enum<?>)constant).name(), constant);
-            enumConstantDirectory = m;
+            directory = new HashMap<>(2 * universe.length);
+            for (T constant : universe) {
+                directory.put(((Enum<?>)constant).name(), constant);
+            }
+            enumConstantDirectory = directory;
         }
-        return enumConstantDirectory;
+        return directory;
     }
-    private transient volatile Map<String, T> enumConstantDirectory = null;
+    private transient volatile Map<String, T> enumConstantDirectory;
 
     /**
      * Casts an object to the class or interface represented

jdk/src/java.base/share/classes/java/lang/System.java

@@ -132,7 +132,7 @@ public final class System {
 
     /* The security manager for the system.
      */
-    private static volatile SecurityManager security = null;
+    private static volatile SecurityManager security;
 
     /**
      * Reassigns the "standard" input stream.
@@ -206,7 +206,7 @@ public final class System {
         setErr0(err);
     }
 
-    private static volatile Console cons = null;
+    private static volatile Console cons;
     /**
      * Returns the unique {@link java.io.Console Console} object associated
      * with the current Java virtual machine, if any.
@@ -216,12 +216,13 @@ public final class System {
      * @since   1.6
      */
      public static Console console() {
-         if (cons == null) {
+         Console c = cons;
+         if (c == null) {
              synchronized (System.class) {
-                 cons = SharedSecrets.getJavaIOAccess().console();
+                 cons = c = SharedSecrets.getJavaIOAccess().console();
              }
          }
-         return cons;
+         return c;
      }
 
     /**

jdk/src/java.base/share/classes/java/lang/Thread.java

@@ -207,12 +207,10 @@ class Thread implements Runnable {
     /* For generating thread ID */
     private static long threadSeqNumber;
 
-    /* Java thread status for tools,
-     * initialized to indicate thread 'not yet started'
+    /*
+     * Java thread status for tools, default indicates thread 'not yet started'
      */
-
-    private volatile int threadStatus = 0;
-
+    private volatile int threadStatus;
 
     private static synchronized long nextThreadID() {
         return ++threadSeqNumber;

jdk/src/java.base/share/classes/java/lang/ref/ReferenceQueue.java

@@ -53,7 +53,7 @@ public class ReferenceQueue<T> {
 
     private static class Lock { };
     private Lock lock = new Lock();
-    private volatile Reference<? extends T> head = null;
+    private volatile Reference<? extends T> head;
     private long queueLength = 0;
 
     boolean enqueue(Reference<? extends T> r) { /* Called only by Reference class */

jdk/src/java.base/share/classes/java/lang/reflect/Parameter.java

@@ -205,7 +205,7 @@ public final class Parameter implements AnnotatedElement {
         return tmp;
     }
 
-    private transient volatile Type parameterTypeCache = null;
+    private transient volatile Type parameterTypeCache;
 
     /**
      * Returns a {@code Class} object that identifies the
@@ -237,7 +237,7 @@ public final class Parameter implements AnnotatedElement {
         return executable.getAnnotatedParameterTypes()[index];
     }
 
-    private transient volatile Class<?> parameterClassCache = null;
+    private transient volatile Class<?> parameterClassCache;
 
     /**
      * Returns {@code true} if this parameter is implicitly declared

jdk/src/java.base/share/classes/java/net/URI.java

@@ -33,7 +33,6 @@ import java.io.Serializable;
 import java.nio.ByteBuffer;
 import java.nio.CharBuffer;
 import java.nio.charset.CharsetDecoder;
-import java.nio.charset.CharsetEncoder;
 import java.nio.charset.CoderResult;
 import java.nio.charset.CodingErrorAction;
 import java.nio.charset.CharacterCodingException;
@@ -495,12 +494,12 @@ public final class URI
     private transient volatile String schemeSpecificPart;
     private transient volatile int hash;        // Zero ==> undefined
 
-    private transient volatile String decodedUserInfo = null;
-    private transient volatile String decodedAuthority = null;
-    private transient volatile String decodedPath = null;
-    private transient volatile String decodedQuery = null;
-    private transient volatile String decodedFragment = null;
-    private transient volatile String decodedSchemeSpecificPart = null;
+    private transient volatile String decodedUserInfo;
+    private transient volatile String decodedAuthority;
+    private transient volatile String decodedPath;
+    private transient volatile String decodedQuery;
+    private transient volatile String decodedFragment;
+    private transient volatile String decodedSchemeSpecificPart;
 
     /**
      * The string form of this URI.

jdk/src/java.base/share/classes/java/nio/Bits.java

@@ -25,9 +25,7 @@
 
 package java.nio;
 
-import java.security.AccessController;
 import java.util.concurrent.atomic.AtomicLong;
-import java.util.concurrent.atomic.LongAdder;
 
 import jdk.internal.misc.JavaNioAccess;
 import jdk.internal.misc.JavaLangRefAccess;
@@ -603,7 +601,8 @@ class Bits {                            // package-private
     private static final AtomicLong reservedMemory = new AtomicLong();
     private static final AtomicLong totalCapacity = new AtomicLong();
     private static final AtomicLong count = new AtomicLong();
-    private static volatile boolean memoryLimitSet = false;
+    private static volatile boolean memoryLimitSet;
+
     // max. number of sleeps during try-reserving with exponentially
     // increasing delay before throwing OutOfMemoryError:
     // 1, 2, 4, 8, 16, 32, 64, 128, 256 (total 511 ms ~ 0.5 s)

jdk/src/java.base/share/classes/java/nio/channels/SelectionKey.java

@@ -26,8 +26,6 @@
 package java.nio.channels;
 
 import java.util.concurrent.atomic.AtomicReferenceFieldUpdater;
-import java.io.IOException;
-
 
 /**
  * A token representing the registration of a {@link SelectableChannel} with a
@@ -363,7 +361,7 @@ public abstract class SelectionKey {
 
     // -- Attachments --
 
-    private volatile Object attachment = null;
+    private volatile Object attachment;
 
     private static final AtomicReferenceFieldUpdater<SelectionKey,Object>
         attachmentUpdater = AtomicReferenceFieldUpdater.newUpdater(

jdk/src/java.base/share/classes/java/nio/channels/spi/AbstractInterruptibleChannel.java

@@ -29,11 +29,7 @@
 package java.nio.channels.spi;
 
 import java.io.IOException;
-import java.lang.reflect.Method;
-import java.lang.reflect.InvocationTargetException;
 import java.nio.channels.*;
-import java.security.AccessController;
-import java.security.PrivilegedAction;
 import jdk.internal.misc.SharedSecrets;
 import sun.nio.ch.Interruptible;
 
@@ -90,7 +86,7 @@ public abstract class AbstractInterruptibleChannel
 {
 
     private final Object closeLock = new Object();
-    private volatile boolean open = true;
+    private volatile boolean closed;
 
     /**
      * Initializes a new instance of this class.
@@ -110,9 +106,9 @@ public abstract class AbstractInterruptibleChannel
      */
     public final void close() throws IOException {
         synchronized (closeLock) {
-            if (!open)
+            if (closed)
                 return;
-            open = false;
+            closed = true;
             implCloseChannel();
         }
     }
@@ -136,7 +132,7 @@ public abstract class AbstractInterruptibleChannel
     protected abstract void implCloseChannel() throws IOException;
 
     public final boolean isOpen() {
-        return open;
+        return !closed;
     }
 
 
@@ -158,9 +154,9 @@ public abstract class AbstractInterruptibleChannel
             interruptor = new Interruptible() {
                     public void interrupt(Thread target) {
                         synchronized (closeLock) {
-                            if (!open)
+                            if (closed)
                                 return;
-                            open = false;
+                            closed = true;
                             interrupted = target;
                             try {
                                 AbstractInterruptibleChannel.this.implCloseChannel();
@@ -202,7 +198,7 @@ public abstract class AbstractInterruptibleChannel
             this.interrupted = null;
             throw new ClosedByInterruptException();
         }
-        if (!completed && !open)
+        if (!completed && closed)
             throw new AsynchronousCloseException();
     }
 

jdk/src/java.base/share/classes/java/nio/charset/Charset.java

@@ -276,7 +276,7 @@ public abstract class Charset
 
     /* -- Static methods -- */
 
-    private static volatile String bugLevel = null;
+    private static volatile String bugLevel;
 
     static boolean atBugLevel(String bl) {              // package-private
         String level = bugLevel;
@@ -324,8 +324,8 @@ public abstract class Charset
     // Cache of the most-recently-returned charsets,
     // along with the names that were used to find them
     //
-    private static volatile Object[] cache1 = null; // "Level 1" cache
-    private static volatile Object[] cache2 = null; // "Level 2" cache
+    private static volatile Object[] cache1; // "Level 1" cache
+    private static volatile Object[] cache2; // "Level 2" cache
 
     private static void cache(String charsetName, Charset cs) {
         cache2 = cache1;

jdk/src/java.base/share/classes/java/security/SecureRandom.java

@@ -124,7 +124,7 @@ public class SecureRandom extends java.util.Random {
     private String algorithm;
 
     // Seed Generator
-    private static volatile SecureRandom seedGenerator = null;
+    private static volatile SecureRandom seedGenerator;
 
     /**
      * Constructs a secure random number generator (RNG) implementing the
@@ -522,10 +522,12 @@ public class SecureRandom extends java.util.Random {
      * @see #setSeed
      */
     public static byte[] getSeed(int numBytes) {
-        if (seedGenerator == null) {
-            seedGenerator = new SecureRandom();
+        SecureRandom seedGen = seedGenerator;
+        if (seedGen == null) {
+            seedGen = new SecureRandom();
+            seedGenerator = seedGen;
         }
-        return seedGenerator.generateSeed(numBytes);
+        return seedGen.generateSeed(numBytes);
     }
 
     /**

jdk/src/java.base/share/classes/java/text/DateFormatSymbols.java

@@ -630,7 +630,9 @@ public class DateFormatSymbols implements Serializable, Cloneable {
             hashCode = 11 * hashCode + Arrays.hashCode(ampms);
             hashCode = 11 * hashCode + Arrays.deepHashCode(getZoneStringsWrapper());
             hashCode = 11 * hashCode + Objects.hashCode(localPatternChars);
-            cachedHashCode = hashCode;
+            if (hashCode != 0) {
+                cachedHashCode = hashCode;
+            }
         }
 
         return hashCode;
@@ -670,12 +672,12 @@ public class DateFormatSymbols implements Serializable, Cloneable {
     private static final ConcurrentMap<Locale, SoftReference<DateFormatSymbols>> cachedInstances
         = new ConcurrentHashMap<>(3);
 
-    private transient int lastZoneIndex = 0;
+    private transient int lastZoneIndex;
 
     /**
      * Cached hash code
      */
-    transient volatile int cachedHashCode = 0;
+    transient volatile int cachedHashCode;
 
     private void initializeData(Locale desiredLocale) {
         locale = desiredLocale;

jdk/src/java.base/share/classes/java/text/DecimalFormatSymbols.java

@@ -42,14 +42,8 @@ import java.io.IOException;
 import java.io.ObjectInputStream;
 import java.io.Serializable;
 import java.text.spi.DecimalFormatSymbolsProvider;
-import java.util.ArrayList;
 import java.util.Currency;
-import java.util.List;
 import java.util.Locale;
-import java.util.MissingResourceException;
-import java.util.ResourceBundle;
-import java.util.concurrent.ConcurrentHashMap;
-import java.util.concurrent.ConcurrentMap;
 import sun.util.locale.provider.LocaleProviderAdapter;
 import sun.util.locale.provider.LocaleServiceProviderPool;
 import sun.util.locale.provider.ResourceBundleBasedAdapter;
@@ -875,7 +869,7 @@ public class DecimalFormatSymbols implements Cloneable, Serializable {
 
     // currency; only the ISO code is serialized.
     private transient Currency currency;
-    private transient volatile boolean currencyInitialized = false;
+    private transient volatile boolean currencyInitialized;
 
     // Proclaim JDK 1.1 FCS compatibility
     static final long serialVersionUID = 5772796243397350300L;

jdk/src/java.base/share/classes/java/util/Locale.java

@@ -62,7 +62,6 @@ import sun.util.locale.ParseStatus;
 import sun.util.locale.provider.LocaleProviderAdapter;
 import sun.util.locale.provider.LocaleResources;
 import sun.util.locale.provider.LocaleServiceProviderPool;
-import sun.util.locale.provider.ResourceBundleBasedAdapter;
 
 /**
  * A <code>Locale</code> object represents a specific geographical, political,
@@ -2016,11 +2015,11 @@ public final class Locale implements Cloneable, Serializable {
     /**
      * Calculated hashcode
      */
-    private transient volatile int hashCodeValue = 0;
+    private transient volatile int hashCodeValue;
 
     private static volatile Locale defaultLocale = initDefault();
-    private static volatile Locale defaultDisplayLocale = null;
-    private static volatile Locale defaultFormatLocale = null;
+    private static volatile Locale defaultDisplayLocale;
+    private static volatile Locale defaultFormatLocale;
 
     private transient volatile String languageTag;
 
@@ -2207,9 +2206,9 @@ public final class Locale implements Cloneable, Serializable {
                 baseLocale.getRegion(), baseLocale.getVariant(), localeExtensions);
     }
 
-    private static volatile String[] isoLanguages = null;
+    private static volatile String[] isoLanguages;
 
-    private static volatile String[] isoCountries = null;
+    private static volatile String[] isoCountries;
 
     private static String convertOldISOCodes(String language) {
         // we accept both the old and the new ISO codes for the languages whose ISO
@@ -2851,7 +2850,7 @@ public final class Locale implements Cloneable, Serializable {
         private final String range;
         private final double weight;
 
-        private volatile int hash = 0;
+        private volatile int hash;
 
         /**
          * Constructs a {@code LanguageRange} using the given {@code range}.
@@ -3108,14 +3107,17 @@ public final class Locale implements Cloneable, Serializable {
          */
         @Override
         public int hashCode() {
-            if (hash == 0) {
-                int result = 17;
-                result = 37*result + range.hashCode();
+            int h = hash;
+            if (h == 0) {
+                h = 17;
+                h = 37*h + range.hashCode();
                 long bitsWeight = Double.doubleToLongBits(weight);
-                result = 37*result + (int)(bitsWeight ^ (bitsWeight >>> 32));
-                hash = result;
+                h = 37*h + (int)(bitsWeight ^ (bitsWeight >>> 32));
+                if (h != 0) {
+                    hash = h;
+                }
             }
-            return hash;
+            return h;
         }
 
         /**

jdk/src/java.base/share/classes/java/util/regex/Pattern.java

@@ -950,7 +950,7 @@ public final class Pattern
      * Boolean indicating this Pattern is compiled; this is necessary in order
      * to lazily compile deserialized Patterns.
      */
-    private transient volatile boolean compiled = false;
+    private transient volatile boolean compiled;
 
     /**
      * The normalized pattern string.
@@ -1332,7 +1332,6 @@ public final class Pattern
         localCount = 0;
 
         // if length > 0, the Pattern is lazily compiled
-        compiled = false;
         if (pattern.length() == 0) {
             root = new Start(lastAccept);
             matchRoot = lastAccept;
@@ -1377,7 +1376,6 @@ public final class Pattern
      * equivalences of the characters.
      */
     private void normalize() {
-        boolean inCharClass = false;
         int lastCodePoint = -1;
 
         // Convert pattern into normalized form
@@ -1551,7 +1549,6 @@ public final class Pattern
         // offset maintains the index in code units.
 loop:   for(int x=0, offset=0; x<nCodePoints; x++, offset+=len) {
             len = countChars(input, offset, 1);
-            boolean skip = false;
             for(int y=x-1; y>=0; y--) {
                 if (combClass[y] == combClass[x]) {
                     continue loop;
@@ -1566,8 +1563,7 @@ loop:   for(int x=0, offset=0; x<nCodePoints; x++, offset+=len) {
                 temp[index++] = prefix + sre;
         }
         String[] result = new String[index];
-        for (int x=0; x<index; x++)
-            result[x] = temp[x];
+        System.arraycopy(temp, 0, result, 0, index);
         return result;
     }
 
@@ -1742,9 +1738,11 @@ loop:   for(int x=0, offset=0; x<nCodePoints; x++, offset+=len) {
     }
 
     Map<String, Integer> namedGroups() {
-        if (namedGroups == null)
-            namedGroups = new HashMap<>(2);
-        return namedGroups;
+        Map<String, Integer> groups = namedGroups;
+        if (groups == null) {
+            namedGroups = groups = new HashMap<>(2);
+        }
+        return groups;
     }
 
     /**

jdk/src/java.base/share/classes/java/util/zip/ZipFile.java

@@ -72,7 +72,7 @@ public
 class ZipFile implements ZipConstants, Closeable {
 
     private final String name;     // zip file name
-    private volatile boolean closeRequested = false;
+    private volatile boolean closeRequested;
     private Source zsrc;
     private ZipCoder zc;
 
@@ -366,7 +366,7 @@ class ZipFile implements ZipConstants, Closeable {
     }
 
     private class ZipFileInflaterInputStream extends InflaterInputStream {
-        private volatile boolean closeRequested = false;
+        private volatile boolean closeRequested;
         private boolean eof = false;
         private final ZipFileInputStream zfin;
 
@@ -653,7 +653,7 @@ class ZipFile implements ZipConstants, Closeable {
      * (possibly compressed) zip file entry.
      */
    private class ZipFileInputStream extends InputStream {
-        private volatile boolean closeRequested = false;
+        private volatile boolean closeRequested;
         private   long pos;     // current position within entry data
         protected long rem;     // number of remaining bytes within entry
         protected long size;    // uncompressed size of this entry

jdk/src/java.base/share/classes/jdk/internal/logger/LazyLoggers.java

@@ -326,20 +326,22 @@ public final class LazyLoggers {
     }
 
     // Do not expose this outside of this package.
-    private static volatile LoggerFinder provider = null;
+    private static volatile LoggerFinder provider;
     private static LoggerFinder accessLoggerFinder() {
-        if (provider == null) {
+        LoggerFinder prov = provider;
+        if (prov == null) {
             // no need to lock: it doesn't matter if we call
             // getLoggerFinder() twice - since LoggerFinder already caches
             // the result.
             // This is just an optimization to avoid the cost of calling
             // doPrivileged every time.
             final SecurityManager sm = System.getSecurityManager();
-            provider = sm == null ? LoggerFinder.getLoggerFinder() :
+            prov = sm == null ? LoggerFinder.getLoggerFinder() :
                 AccessController.doPrivileged(
                         (PrivilegedAction<LoggerFinder>)LoggerFinder::getLoggerFinder);
+            provider = prov;
         }
-        return provider;
+        return prov;
     }
 
     // Avoid using lambda here as lazy loggers could be created early

jdk/src/java.base/share/classes/sun/misc/VM.java

@@ -27,9 +27,6 @@ package sun.misc;
 
 import static java.lang.Thread.State.*;
 import java.util.Properties;
-import java.util.HashMap;
-import java.util.Map;
-import java.util.Set;
 
 public class VM {
 
@@ -288,10 +285,10 @@ public class VM {
     }
 
     /* Current count of objects pending for finalization */
-    private static volatile int finalRefCount = 0;
+    private static volatile int finalRefCount;
 
     /* Peak count of objects pending for finalization */
-    private static volatile int peakFinalRefCount = 0;
+    private static volatile int peakFinalRefCount;
 
     /*
      * Gets the number of objects pending for finalization.

jdk/src/java.base/share/classes/sun/net/www/http/HttpCapture.java

@@ -54,12 +54,12 @@ import sun.util.logging.PlatformLogger;
  * @author jccollet
  */
 public class HttpCapture {
-    private File file = null;
+    private File file;
     private boolean incoming = true;
-    private BufferedWriter out = null;
-    private static boolean initialized = false;
-    private static volatile ArrayList<Pattern> patterns = null;
-    private static volatile ArrayList<String> capFiles = null;
+    private BufferedWriter out;
+    private static boolean initialized;
+    private static volatile ArrayList<Pattern> patterns;
+    private static volatile ArrayList<String> capFiles;
 
     private static synchronized void init() {
         initialized = true;

jdk/src/java.base/share/classes/sun/net/www/http/HttpClient.java

@@ -98,7 +98,7 @@ public class HttpClient extends NetworkClient {
     // from previous releases.
     private static boolean retryPostProp = true;
 
-    volatile boolean keepingAlive = false;     /* this is a keep-alive connection */
+    volatile boolean keepingAlive;    /* this is a keep-alive connection */
     int keepAliveConnections = -1;    /* number of keep-alives left */
 
     /**Idle timeout value, in milliseconds. Zero means infinity,

jdk/src/java.base/share/classes/sun/nio/ch/AsynchronousServerSocketChannelImpl.java

@@ -51,14 +51,14 @@ abstract class AsynchronousServerSocketChannelImpl
     protected final FileDescriptor fd;
 
     // the local address to which the channel's socket is bound
-    protected volatile InetSocketAddress localAddress = null;
+    protected volatile InetSocketAddress localAddress;
 
     // need this lock to set local address
     private final Object stateLock = new Object();
 
     // close support
     private ReadWriteLock closeLock = new ReentrantReadWriteLock();
-    private volatile boolean open = true;
+    private volatile boolean closed;
 
     // set true when accept operation is cancelled
     private volatile boolean acceptKilled;
@@ -73,7 +73,7 @@ abstract class AsynchronousServerSocketChannelImpl
 
     @Override
     public final boolean isOpen() {
-        return open;
+        return !closed;
     }
 
     /**
@@ -102,9 +102,9 @@ abstract class AsynchronousServerSocketChannelImpl
         // synchronize with any threads using file descriptor/handle
         closeLock.writeLock().lock();
         try {
-            if (!open)
+            if (closed)
                 return;     // already closed
-            open = false;
+            closed = true;
         } finally {
             closeLock.writeLock().unlock();
         }

jdk/src/java.base/share/classes/sun/nio/ch/AsynchronousSocketChannelImpl.java

@@ -54,8 +54,8 @@ abstract class AsynchronousSocketChannelImpl
     // protects state, localAddress, and remoteAddress
     protected final Object stateLock = new Object();
 
-    protected volatile InetSocketAddress localAddress = null;
-    protected volatile InetSocketAddress remoteAddress = null;
+    protected volatile InetSocketAddress localAddress;
+    protected volatile InetSocketAddress remoteAddress;
 
     // State, increases monotonically
     static final int ST_UNINITIALIZED = -1;
@@ -78,7 +78,7 @@ abstract class AsynchronousSocketChannelImpl
 
     // close support
     private final ReadWriteLock closeLock = new ReentrantReadWriteLock();
-    private volatile boolean open = true;
+    private volatile boolean closed;
 
     // set true when exclusive binding is on and SO_REUSEADDR is emulated
     private boolean isReuseAddress;
@@ -106,7 +106,7 @@ abstract class AsynchronousSocketChannelImpl
 
     @Override
     public final boolean isOpen() {
-        return open;
+        return !closed;
     }
 
     /**
@@ -135,9 +135,9 @@ abstract class AsynchronousSocketChannelImpl
         // synchronize with any threads initiating asynchronous operations
         closeLock.writeLock().lock();
         try {
-            if (!open)
+            if (closed)
                 return;     // already closed
-            open = false;
+            closed = true;
         } finally {
             closeLock.writeLock().unlock();
         }

jdk/src/java.base/share/classes/sun/nio/ch/DatagramChannelImpl.java

@@ -58,8 +58,8 @@ class DatagramChannelImpl
     private final ProtocolFamily family;
 
     // IDs of native threads doing reads and writes, for signalling
-    private volatile long readerThread = 0;
-    private volatile long writerThread = 0;
+    private volatile long readerThread;
+    private volatile long writerThread;
 
     // Cached InetAddress and port for unconnected DatagramChannels
     // used by receive0

jdk/src/java.base/share/classes/sun/nio/ch/DatagramSocketAdaptor.java

@@ -46,7 +46,7 @@ public class DatagramSocketAdaptor
     private final DatagramChannelImpl dc;
 
     // Timeout "option" value for receives
-    private volatile int timeout = 0;
+    private volatile int timeout;
 
     // ## super will create a useless impl
     private DatagramSocketAdaptor(DatagramChannelImpl dc) throws IOException {

jdk/src/java.base/share/classes/sun/nio/ch/FileLockImpl.java

@@ -31,7 +31,7 @@ import java.nio.channels.*;
 public class FileLockImpl
     extends FileLock
 {
-    private volatile boolean valid = true;
+    private volatile boolean invalid;
 
     FileLockImpl(FileChannel channel, long position, long size, boolean shared)
     {
@@ -44,25 +44,25 @@ public class FileLockImpl
     }
 
     public boolean isValid() {
-        return valid;
+        return !invalid;
     }
 
     void invalidate() {
         assert Thread.holdsLock(this);
-        valid = false;
+        invalid = true;
     }
 
     public synchronized void release() throws IOException {
         Channel ch = acquiredBy();
         if (!ch.isOpen())
             throw new ClosedChannelException();
-        if (valid) {
+        if (isValid()) {
             if (ch instanceof FileChannelImpl)
                 ((FileChannelImpl)ch).release(this);
             else if (ch instanceof AsynchronousFileChannelImpl)
                 ((AsynchronousFileChannelImpl)ch).release(this);
             else throw new AssertionError();
-            valid = false;
+            invalidate();
         }
     }
 }

jdk/src/java.base/share/classes/sun/nio/ch/MembershipKeyImpl.java

@@ -43,8 +43,7 @@ class MembershipKeyImpl
     private final NetworkInterface interf;
     private final InetAddress source;
 
-    // true when key is valid
-    private volatile boolean valid = true;
+    private volatile boolean invalid;
 
     // lock used when creating or accessing blockedSet
     private Object stateLock = new Object();
@@ -134,12 +133,12 @@ class MembershipKeyImpl
     }
 
     public boolean isValid() {
-        return valid;
+        return !invalid;
     }
 
     // package-private
     void invalidate() {
-        valid = false;
+        invalid = true;
     }
 
     public void drop() {

jdk/src/java.base/share/classes/sun/nio/ch/Net.java

@@ -32,7 +32,6 @@ import java.nio.channels.*;
 import java.util.*;
 import java.security.AccessController;
 import java.security.PrivilegedAction;
-import java.security.PrivilegedExceptionAction;
 import sun.net.ExtendedOptionsImpl;
 
 
@@ -55,7 +54,7 @@ public class Net {
 
     // -- Miscellaneous utilities --
 
-    private static volatile boolean checkedIPv6 = false;
+    private static volatile boolean checkedIPv6;
     private static volatile boolean isIPv6Available;
 
     /**

jdk/src/java.base/share/classes/sun/nio/ch/ServerSocketAdaptor.java

@@ -45,7 +45,7 @@ public class ServerSocketAdaptor                        // package-private
     private final ServerSocketChannelImpl ssc;
 
     // Timeout "option" value for accepts
-    private volatile int timeout = 0;
+    private volatile int timeout;
 
     public static ServerSocket create(ServerSocketChannelImpl ssc) {
         try {

jdk/src/java.base/share/classes/sun/nio/ch/ServerSocketChannelImpl.java

@@ -54,7 +54,7 @@ class ServerSocketChannelImpl
     private int fdVal;
 
     // ID of native thread currently blocked in this channel, for signalling
-    private volatile long thread = 0;
+    private volatile long thread;
 
     // Lock held by thread currently blocked in this channel
     private final Object lock = new Object();

jdk/src/java.base/share/classes/sun/nio/ch/SocketAdaptor.java

@@ -26,13 +26,11 @@
 package sun.nio.ch;
 
 import java.io.*;
-import java.lang.ref.*;
 import java.net.*;
 import java.nio.*;
 import java.nio.channels.*;
 import java.security.AccessController;
 import java.security.PrivilegedExceptionAction;
-import java.util.*;
 
 
 // Make a socket channel look like a socket.
@@ -55,7 +53,7 @@ public class SocketAdaptor
     private final SocketChannelImpl sc;
 
     // Timeout "option" value for reads
-    private volatile int timeout = 0;
+    private volatile int timeout;
 
     private SocketAdaptor(SocketChannelImpl sc) throws SocketException {
         super((SocketImpl) null);

jdk/src/java.base/share/classes/sun/nio/ch/SocketChannelImpl.java

@@ -56,8 +56,8 @@ class SocketChannelImpl
     private final int fdVal;
 
     // IDs of native threads doing reads and writes, for signalling
-    private volatile long readerThread = 0;
-    private volatile long writerThread = 0;
+    private volatile long readerThread;
+    private volatile long writerThread;
 
     // Lock held by current reading or connecting thread
     private final Object readLock = new Object();

jdk/src/java.base/share/classes/sun/nio/ch/Util.java

@@ -25,13 +25,10 @@
 
 package sun.nio.ch;
 
-import java.lang.ref.SoftReference;
 import java.lang.reflect.*;
-import java.io.IOException;
 import java.io.FileDescriptor;
 import java.nio.ByteBuffer;
 import java.nio.MappedByteBuffer;
-import java.nio.channels.*;
 import java.security.AccessController;
 import java.security.PrivilegedAction;
 import java.util.*;
@@ -295,7 +292,7 @@ public class Util {
         return pageSize;
     }
 
-    private static volatile Constructor<?> directByteBufferConstructor = null;
+    private static volatile Constructor<?> directByteBufferConstructor;
 
     private static void initDBBConstructor() {
         AccessController.doPrivileged(new PrivilegedAction<Void>() {
@@ -340,7 +337,7 @@ public class Util {
         return dbb;
     }
 
-    private static volatile Constructor<?> directByteBufferRConstructor = null;
+    private static volatile Constructor<?> directByteBufferRConstructor;
 
     private static void initDBBRConstructor() {
         AccessController.doPrivileged(new PrivilegedAction<Void>() {
@@ -388,7 +385,7 @@ public class Util {
 
     // -- Bug compatibility --
 
-    private static volatile String bugLevel = null;
+    private static volatile String bugLevel;
 
     static boolean atBugLevel(String bl) {              // package-private
         if (bugLevel == null) {

jdk/src/java.base/share/classes/sun/nio/cs/StreamDecoder.java

@@ -39,10 +39,10 @@ public class StreamDecoder extends Reader
     private static final int MIN_BYTE_BUFFER_SIZE = 32;
     private static final int DEFAULT_BYTE_BUFFER_SIZE = 8192;
 
-    private volatile boolean isOpen = true;
+    private volatile boolean closed;
 
     private void ensureOpen() throws IOException {
-        if (!isOpen)
+        if (closed)
             throw new IOException("Stream closed");
     }
 
@@ -188,15 +188,15 @@ public class StreamDecoder extends Reader
 
     public void close() throws IOException {
         synchronized (lock) {
-            if (!isOpen)
+            if (closed)
                 return;
             implClose();
-            isOpen = false;
+            closed = true;
         }
     }
 
     private boolean isOpen() {
-        return isOpen;
+        return !closed;
     }
 
 

jdk/src/java.base/share/classes/sun/nio/cs/StreamEncoder.java

@@ -38,10 +38,10 @@ public class StreamEncoder extends Writer
 
     private static final int DEFAULT_BYTE_BUFFER_SIZE = 8192;
 
-    private volatile boolean isOpen = true;
+    private volatile boolean closed;
 
     private void ensureOpen() throws IOException {
-        if (!isOpen)
+        if (closed)
             throw new IOException("Stream closed");
     }
 
@@ -156,15 +156,15 @@ public class StreamEncoder extends Writer
 
     public void close() throws IOException {
         synchronized (lock) {
-            if (!isOpen)
+            if (closed)
                 return;
             implClose();
-            isOpen = false;
+            closed = true;
         }
     }
 
     private boolean isOpen() {
-        return isOpen;
+        return !closed;
     }
 
 

jdk/src/java.base/share/classes/sun/reflect/MethodAccessorGenerator.java

@@ -44,9 +44,9 @@ class MethodAccessorGenerator extends AccessorGenerator {
     // Only used if forSerialization is true
     private static final short NUM_SERIALIZATION_CPOOL_ENTRIES = (short) 2;
 
-    private static volatile int methodSymnum = 0;
-    private static volatile int constructorSymnum = 0;
-    private static volatile int serializationConstructorSymnum = 0;
+    private static volatile int methodSymnum;
+    private static volatile int constructorSymnum;
+    private static volatile int serializationConstructorSymnum;
 
     private Class<?>   declaringClass;
     private Class<?>[] parameterTypes;

jdk/src/java.base/share/classes/sun/reflect/annotation/AnnotationInvocationHandler.java

@@ -299,7 +299,7 @@ class AnnotationInvocationHandler implements InvocationHandler, Serializable {
                 }});
     }
 
-    private transient volatile Method[] memberMethods = null;
+    private transient volatile Method[] memberMethods;
 
     /**
      * Validates that a method is structurally appropriate for an

jdk/src/java.base/share/classes/sun/security/ssl/SSLSessionImpl.java

@@ -130,7 +130,7 @@ final class SSLSessionImpl extends ExtendedSSLSession {
      * also since counters make shorter debugging IDs than the big ones
      * we use in the protocol for uniqueness-over-time.
      */
-    private static volatile int counter = 0;
+    private static volatile int counter;
 
     /*
      * Use of session caches is globally enabled/disabled.

jdk/src/java.base/share/classes/sun/security/x509/X509CRLImpl.java

@@ -1290,7 +1290,7 @@ public class X509CRLImpl extends X509CRL implements DerEncoder {
             implements Comparable<X509IssuerSerial> {
         final X500Principal issuer;
         final BigInteger serial;
-        volatile int hashcode = 0;
+        volatile int hashcode;
 
         /**
          * Create an X509IssuerSerial.
@@ -1358,13 +1358,16 @@ public class X509CRLImpl extends X509CRL implements DerEncoder {
          * @return the hash code value
          */
         public int hashCode() {
-            if (hashcode == 0) {
-                int result = 17;
-                result = 37*result + issuer.hashCode();
-                result = 37*result + serial.hashCode();
-                hashcode = result;
+            int h = hashcode;
+            if (h == 0) {
+                h = 17;
+                h = 37*h + issuer.hashCode();
+                h = 37*h + serial.hashCode();
+                if (h != 0) {
+                    hashcode = h;
+                }
             }
-            return hashcode;
+            return h;
         }
 
         @Override

jdk/src/java.base/share/classes/sun/util/calendar/CalendarSystem.java

@@ -25,13 +25,6 @@
 
 package sun.util.calendar;
 
-import java.io.File;
-import java.io.FileInputStream;
-import java.io.IOException;
-import java.security.AccessController;
-import java.security.PrivilegedActionException;
-import java.security.PrivilegedExceptionAction;
-import java.util.Properties;
 import java.util.TimeZone;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentMap;
@@ -76,7 +69,7 @@ public abstract class CalendarSystem {
 
     /////////////////////// Calendar Factory Methods /////////////////////////
 
-    private static volatile boolean initialized = false;
+    private static volatile boolean initialized;
 
     // Map of calendar names and calendar class names
     private static ConcurrentMap<String, String> names;

jdk/src/java.base/share/classes/sun/util/locale/BaseLocale.java

@@ -46,7 +46,7 @@ public final class BaseLocale {
     private final String region;
     private final String variant;
 
-    private volatile int hash = 0;
+    private volatile int hash;
 
     // This method must be called only when creating the Locale.* constants.
     private BaseLocale(String language, String region) {
@@ -147,7 +147,9 @@ public final class BaseLocale {
             h = 31 * h + script.hashCode();
             h = 31 * h + region.hashCode();
             h = 31 * h + variant.hashCode();
-            hash = h;
+            if (h != 0) {
+                hash = h;
+            }
         }
         return h;
     }

jdk/src/java.base/share/classes/sun/util/locale/provider/JRELocaleProviderAdapter.java

@@ -114,20 +114,20 @@ public class JRELocaleProviderAdapter extends LocaleProviderAdapter implements R
         }
     }
 
-    private volatile BreakIteratorProvider breakIteratorProvider = null;
-    private volatile CollatorProvider collatorProvider = null;
-    private volatile DateFormatProvider dateFormatProvider = null;
-    private volatile DateFormatSymbolsProvider dateFormatSymbolsProvider = null;
-    private volatile DecimalFormatSymbolsProvider decimalFormatSymbolsProvider = null;
-    private volatile NumberFormatProvider numberFormatProvider = null;
-
-    private volatile CurrencyNameProvider currencyNameProvider = null;
-    private volatile LocaleNameProvider localeNameProvider = null;
-    private volatile TimeZoneNameProvider timeZoneNameProvider = null;
-    private volatile CalendarDataProvider calendarDataProvider = null;
-    private volatile CalendarNameProvider calendarNameProvider = null;
-
-    private volatile CalendarProvider calendarProvider = null;
+    private volatile BreakIteratorProvider breakIteratorProvider;
+    private volatile CollatorProvider collatorProvider;
+    private volatile DateFormatProvider dateFormatProvider;
+    private volatile DateFormatSymbolsProvider dateFormatSymbolsProvider;
+    private volatile DecimalFormatSymbolsProvider decimalFormatSymbolsProvider;
+    private volatile NumberFormatProvider numberFormatProvider;
+
+    private volatile CurrencyNameProvider currencyNameProvider;
+    private volatile LocaleNameProvider localeNameProvider;
+    private volatile TimeZoneNameProvider timeZoneNameProvider;
+    private volatile CalendarDataProvider calendarDataProvider;
+    private volatile CalendarNameProvider calendarNameProvider;
+
+    private volatile CalendarProvider calendarProvider;
 
     /*
      * Getter methods for java.text.spi.* providers

jdk/src/java.base/share/classes/sun/util/locale/provider/LocaleProviderAdapter.java

@@ -107,7 +107,7 @@ public abstract class LocaleProviderAdapter {
      * Default fallback adapter type, which should return something meaningful in any case.
      * This is either CLDR or FALLBACK.
      */
-    static volatile LocaleProviderAdapter.Type defaultLocaleProviderAdapter = null;
+    static volatile LocaleProviderAdapter.Type defaultLocaleProviderAdapter;
 
     /**
      * Adapter lookup cache.

jdk/src/java.base/share/classes/sun/util/resources/OpenListResourceBundle.java

@@ -164,6 +164,6 @@ public abstract class OpenListResourceBundle extends ResourceBundle {
         return new HashSet<>();
     }
 
-    private volatile Map<String, Object> lookup = null;
+    private volatile Map<String, Object> lookup;
     private volatile Set<String> keyset;
 }

jdk/src/java.base/unix/classes/sun/nio/ch/SinkChannelImpl.java

@@ -47,7 +47,7 @@ class SinkChannelImpl
     int fdVal;
 
     // ID of native thread doing write, for signalling
-    private volatile long thread = 0;
+    private volatile long thread;
 
     // Lock held by current reading thread
     private final Object lock = new Object();

jdk/src/java.base/unix/classes/sun/nio/ch/SourceChannelImpl.java

@@ -47,7 +47,7 @@ class SourceChannelImpl
     int fdVal;
 
     // ID of native thread doing read, for signalling
-    private volatile long thread = 0;
+    private volatile long thread;
 
     // Lock held by current reading thread
     private final Object lock = new Object();

jdk/src/java.base/unix/classes/sun/nio/fs/MimeTypesFileTypeDetector.java

@@ -52,7 +52,7 @@ class MimeTypesFileTypeDetector extends AbstractFileTypeDetector {
     private Map<String,String> mimeTypeMap;
 
     // set to true when file loaded
-    private volatile boolean loaded = false;
+    private volatile boolean loaded;
 
     public MimeTypesFileTypeDetector(Path filePath) {
         mimeTypesFile = filePath;

jdk/src/java.base/windows/classes/sun/nio/ch/WindowsSelectorImpl.java

@@ -119,7 +119,7 @@ final class WindowsSelectorImpl extends SelectorImpl {
 
     // Lock for interrupt triggering and clearing
     private final Object interruptLock = new Object();
-    private volatile boolean interruptTriggered = false;
+    private volatile boolean interruptTriggered;
 
     WindowsSelectorImpl(SelectorProvider sp) throws IOException {
         super(sp);