Refactor synchronized to ReentrantLock (#2081)

ebean-core/src/main/java/io/ebeaninternal/server/cache/DefaultCacheHolder.java

@@ -18,6 +18,7 @@ import org.slf4j.LoggerFactory;
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentSkipListSet;
+import java.util.concurrent.locks.ReentrantLock;
 
 /**
  * Manages the construction of caches.
@@ -26,17 +27,14 @@ class DefaultCacheHolder {
 
   private static final Logger log = LoggerFactory.getLogger("io.ebean.cache.ALL");
 
+  private final ReentrantLock lock = new ReentrantLock(false);
   private final ConcurrentHashMap<String, ServerCache> allCaches = new ConcurrentHashMap<>();
-
   private final ConcurrentHashMap<String, Set<String>> collectIdCaches = new ConcurrentHashMap<>();
 
   private final ServerCacheFactory cacheFactory;
-
   private final ServerCacheOptions beanDefault;
   private final ServerCacheOptions queryDefault;
-
   private final CurrentTenantProvider tenantProvider;
-
   private final QueryCacheEntryValidate queryCacheEntryValidate;
 
   DefaultCacheHolder(CacheManagerOptions builder) {
@@ -87,8 +85,11 @@ class DefaultCacheHolder {
   private ServerCache createCache(Class<?> beanType, ServerCacheType type, String key, String shortName) {
     ServerCacheOptions options = getCacheOptions(beanType, type);
     if (type == ServerCacheType.COLLECTION_IDS) {
-      synchronized (this) {
+      lock.lock();
+      try {
         collectIdCaches.computeIfAbsent(beanType.getName(), s -> new ConcurrentSkipListSet<>()).add(key);
+      } finally {
+        lock.unlock();
       }
     }
     return cacheFactory.createCache(new ServerCacheConfig(type, key, shortName, options, tenantProvider, queryCacheEntryValidate));

ebean-core/src/main/java/io/ebeaninternal/server/cluster/ClusterManager.java

@@ -9,6 +9,7 @@ import org.slf4j.LoggerFactory;
 import java.util.Iterator;
 import java.util.ServiceLoader;
 import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.locks.ReentrantLock;
 
 /**
  * Manages the cluster service.
@@ -17,6 +18,8 @@ public class ClusterManager implements ServerLookup {
 
   private static final Logger clusterLogger = LoggerFactory.getLogger("io.ebean.Cluster");
 
+  private final ReentrantLock lock = new ReentrantLock(false);
+
   private final ConcurrentHashMap<String, EbeanServer> serverMap = new ConcurrentHashMap<>();
 
   private final Object monitor = new Object();
@@ -51,18 +54,24 @@ public class ClusterManager implements ServerLookup {
   }
 
   public void registerServer(EbeanServer server) {
-    synchronized (monitor) {
+    lock.lock();
+    try {
       serverMap.put(server.getName(), server);
       if (!started) {
         startup();
       }
+    } finally {
+      lock.unlock();
     }
   }
 
   @Override
   public EbeanServer getServer(String name) {
-    synchronized (monitor) {
+    lock.lock();
+    try {
       return serverMap.get(name);
+    } finally {
+      lock.unlock();
     }
   }
 

ebean-core/src/main/java/io/ebeaninternal/server/core/DefaultContainer.java

@@ -26,6 +26,7 @@ import java.sql.Connection;
 import java.sql.SQLException;
 import java.util.List;
 import java.util.ServiceLoader;
+import java.util.concurrent.locks.ReentrantLock;
 
 /**
  * Default Server side implementation of ServerFactory.
@@ -34,6 +35,7 @@ public class DefaultContainer implements SpiContainer {
 
   private static final Logger logger = LoggerFactory.getLogger("io.ebean.internal.DefaultContainer");
 
+  private final ReentrantLock lock = new ReentrantLock(false);
   private final ClusterManager clusterManager;
 
   public DefaultContainer(ContainerConfig containerConfig) {
@@ -72,7 +74,8 @@ public class DefaultContainer implements SpiContainer {
    */
   @Override
   public SpiEbeanServer createServer(DatabaseConfig config) {
-    synchronized (this) {
+    lock.lock();
+    try {
       applyConfigServices(config);
       setNamingConvention(config);
       BootupClasses bootupClasses = getBootupClasses(config);
@@ -114,6 +117,8 @@ public class DefaultContainer implements SpiContainer {
       }
       DbOffline.reset();
       return server;
+    } finally {
+      lock.unlock();
     }
   }
 

ebean-core/src/main/java/io/ebeaninternal/server/core/DefaultServer.java

@@ -36,11 +36,13 @@ import io.ebean.Version;
 import io.ebean.annotation.Platform;
 import io.ebean.annotation.TxIsolation;
 import io.ebean.bean.BeanCollection;
+import io.ebean.bean.BeanLoader;
 import io.ebean.bean.CallOrigin;
 import io.ebean.bean.EntityBean;
 import io.ebean.bean.EntityBeanIntercept;
 import io.ebean.bean.PersistenceContext;
 import io.ebean.bean.PersistenceContext.WithOption;
+import io.ebean.bean.SingleBeanLoader;
 import io.ebean.cache.ServerCacheManager;
 import io.ebean.common.CopyOnFirstWriteList;
 import io.ebean.config.CurrentTenantProvider;
@@ -142,6 +144,7 @@ import java.util.Optional;
 import java.util.Set;
 import java.util.Spliterator;
 import java.util.concurrent.Callable;
+import java.util.concurrent.locks.ReentrantLock;
 import java.util.function.Consumer;
 import java.util.function.Function;
 import java.util.function.Predicate;
@@ -157,98 +160,47 @@ public final class DefaultServer implements SpiServer, SpiEbeanServer {
 
   private static final Logger logger = LoggerFactory.getLogger(DefaultServer.class);
 
+  private final ReentrantLock lock = new ReentrantLock(false);
   private final DatabaseConfig config;
-
   private final String serverName;
-
   private final DatabasePlatform databasePlatform;
-
   private final TransactionManager transactionManager;
-
   private final QueryPlanManager queryPlanManager;
-
   private final ExtraMetrics extraMetrics;
-
   private final DataTimeZone dataTimeZone;
-
-  /**
-   * Clock to use for WhenModified and WhenCreated.
-   */
   private final ClockService clockService;
-
   private final CallOriginFactory callStackFactory;
-
-  /**
-   * Handles the save, delete, updateSql CallableSql.
-   */
   private final Persister persister;
-
   private final OrmQueryEngine queryEngine;
-
   private final RelationalQueryEngine relationalQueryEngine;
   private final DtoQueryEngine dtoQueryEngine;
-
   private final ServerCacheManager serverCacheManager;
-
   private final DtoBeanManager dtoBeanManager;
   private final BeanDescriptorManager beanDescriptorManager;
-
   private final AutoTuneService autoTuneService;
-
   private final ReadAuditPrepare readAuditPrepare;
-
   private final ReadAuditLogger readAuditLogger;
-
   private final CQueryEngine cqueryEngine;
-
   private final List<Plugin> serverPlugins;
-
   private final SpiDdlGenerator ddlGenerator;
-
   private final ScriptRunner scriptRunner;
-
   private final ExpressionFactory expressionFactory;
-
   private final SpiBackgroundExecutor backgroundExecutor;
-
   private final DefaultBeanLoader beanLoader;
-
   private final EncryptKeyManager encryptKeyManager;
-
   private final SpiJsonContext jsonContext;
-
   private final DocumentStore documentStore;
-
   private final MetaInfoManager metaInfoManager;
-
   private final CurrentTenantProvider currentTenantProvider;
-
   private final SpiLogManager logManager;
-
-  /**
-   * The default PersistenceContextScope used if it is not explicitly set on a query.
-   */
   private final PersistenceContextScope defaultPersistenceContextScope;
-
-  /**
-   * Flag set when the server has shutdown.
-   */
-  private boolean shutdown;
-
-  /**
-   * The default batch size for lazy loading beans or collections.
-   */
   private final int lazyLoadBatchSize;
-
   private final int queryBatchSize;
-
   private final boolean updateAllPropertiesInBatch;
-
   private final long slowQueryMicros;
-
   private final SlowQueryListener slowQueryListener;
-
   private final boolean disableL2Cache;
+  private boolean shutdown;
 
   /**
    * Create the DefaultServer.
@@ -452,8 +404,11 @@ public final class DefaultServer implements SpiServer, SpiEbeanServer {
 
   @Override
   public void shutdown() {
-    synchronized (this) {
+    lock.lock();
+    try {
       shutdownInternal(true, false);
+    } finally {
+      lock.unlock();
     }
   }
 
@@ -462,10 +417,12 @@ public final class DefaultServer implements SpiServer, SpiEbeanServer {
    */
   @Override
   public void shutdown(boolean shutdownDataSource, boolean deregisterDriver) {
-    synchronized (this) {
-      // Unregister from JVM Shutdown hook
+    lock.lock();
+    try {
       ShutdownManager.unregisterDatabase(this);
       shutdownInternal(shutdownDataSource, deregisterDriver);
+    } finally {
+      lock.unlock();
     }
   }
 
@@ -575,6 +532,11 @@ public final class DefaultServer implements SpiServer, SpiEbeanServer {
     beanLoader.loadBean(loadRequest);
   }
 
+  @Override
+  public BeanLoader beanLoader() {
+    return new SingleBeanLoader.Dflt(this);
+  }
+
   @Override
   public void loadBean(EntityBeanIntercept ebi) {
     beanLoader.loadBean(ebi);

ebean-core/src/main/java/io/ebeaninternal/server/core/InternString.java

@@ -1,6 +1,7 @@
 package io.ebeaninternal.server.core;
 
 import java.util.HashMap;
+import java.util.concurrent.locks.ReentrantLock;
 
 /**
  * Used to reduce memory consumption of strings used in deployment processing.
@@ -12,6 +13,8 @@ public final class InternString {
 
   private static final HashMap<String, String> map = new HashMap<>();
 
+  private static final ReentrantLock lock = new ReentrantLock(false);
+
   /**
    * Return the shared instance of this string.
    */
@@ -19,8 +22,8 @@ public final class InternString {
     if (s == null) {
       return null;
     }
-    //noinspection SynchronizationOnStaticField
-    synchronized (map) {
+    lock.lock();
+    try {
       String v = map.get(s);
       if (v != null) {
         return v;
@@ -28,6 +31,8 @@ public final class InternString {
         map.put(s, s);
         return s;
       }
+    } finally {
+      lock.unlock();
     }
   }
 }

ebean-core/src/main/java/io/ebeaninternal/server/idgen/UuidV1RndIdGenerator.java

@@ -7,6 +7,7 @@ import java.security.SecureRandom;
 import java.util.UUID;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.atomic.AtomicLong;
+import java.util.concurrent.locks.ReentrantLock;
 
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -44,6 +45,8 @@ public class UuidV1RndIdGenerator implements PlatformIdGenerator {
 
   private AtomicLong nanoToMilliOffset = new AtomicLong(currentUuidTime());
 
+  private final ReentrantLock lock = new ReentrantLock(false);
+
 
   /**
    * Returns the uuid epoch.
@@ -106,7 +109,8 @@ public class UuidV1RndIdGenerator implements PlatformIdGenerator {
           logger.info("Clock skew of {} ms detected", delta / -10000);
           // The clock was adjusted back about 2 seconds, or we were generating a lot of ids too fast
           // if so, we try to set the current as last and also increment the clockSeq.
-          synchronized (this) {
+          lock.lock();
+          try {
             if (clockSeq.compareAndSet(seq, seq + 1)) {
               timeStamp.set(current);
               saveState();
@@ -114,6 +118,8 @@ public class UuidV1RndIdGenerator implements PlatformIdGenerator {
             } else {
               continue;
             }
+          } finally {
+            lock.unlock();
           }
         }
         // If current is in the future (most of the cases) try to set it.

ebean-core/src/main/java/io/ebeaninternal/server/lib/DaemonExecutorService.java

@@ -6,6 +6,7 @@ import org.slf4j.LoggerFactory;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.concurrent.TimeUnit;
+import java.util.concurrent.locks.ReentrantLock;
 
 /**
  * A "CachedThreadPool" based on Daemon threads.
@@ -16,6 +17,8 @@ public final class DaemonExecutorService {
 
   private static final Logger logger = LoggerFactory.getLogger(DaemonExecutorService.class);
 
+  private final ReentrantLock lock = new ReentrantLock(false);
+
   private final String namePrefix;
 
   private final int shutdownWaitSeconds;
@@ -49,7 +52,8 @@ public final class DaemonExecutorService {
    * </p>
    */
   public void shutdown() {
-    synchronized (this) {
+    lock.lock();
+    try {
       if (service.isShutdown()) {
         logger.debug("DaemonExecutorService[{}] already shut down", namePrefix);
         return;
@@ -66,6 +70,8 @@ public final class DaemonExecutorService {
         logger.error("Error during shutdown of DaemonThreadPool[" + namePrefix + "]", e);
         e.printStackTrace();
       }
+    } finally {
+      lock.unlock();
     }
   }
 

ebean-core/src/main/java/io/ebeaninternal/server/lib/DaemonScheduleThreadPool.java

@@ -5,6 +5,7 @@ import org.slf4j.LoggerFactory;
 
 import java.util.concurrent.ScheduledThreadPoolExecutor;
 import java.util.concurrent.TimeUnit;
+import java.util.concurrent.locks.ReentrantLock;
 
 /**
  * Daemon based ScheduleThreadPool.
@@ -16,6 +17,8 @@ public final class DaemonScheduleThreadPool extends ScheduledThreadPoolExecutor
 
   private static final Logger logger = LoggerFactory.getLogger(DaemonScheduleThreadPool.class);
 
+  private final ReentrantLock lock = new ReentrantLock(false);
+
   private final String namePrefix;
 
   private final int shutdownWaitSeconds;
@@ -38,7 +41,8 @@ public final class DaemonScheduleThreadPool extends ScheduledThreadPoolExecutor
    */
   @Override
   public void shutdown() {
-    synchronized (this) {
+    lock.lock();
+    try {
       if (super.isShutdown()) {
         logger.debug("DaemonScheduleThreadPool {} already shut down", namePrefix);
         return;
@@ -55,6 +59,8 @@ public final class DaemonScheduleThreadPool extends ScheduledThreadPoolExecutor
         logger.error("Error during shutdown of " + namePrefix, e);
         e.printStackTrace();
       }
+    } finally {
+      lock.unlock();
     }
   }
 }

ebean-core/src/main/java/io/ebeaninternal/server/loadcontext/DLoadBaseContext.java

@@ -7,11 +7,15 @@ import io.ebeaninternal.api.SpiQuery;
 import io.ebeaninternal.server.deploy.BeanDescriptor;
 import io.ebeaninternal.server.querydefn.OrmQueryProperties;
 
+import java.util.concurrent.locks.ReentrantLock;
+
 /**
  * Base class for Bean and BeanCollection loading (lazy loading and query join loading).
  */
 abstract class DLoadBaseContext {
 
+  protected final ReentrantLock lock = new ReentrantLock(false);
+
   protected final DLoadContext parent;
 
   protected final BeanDescriptor<?> desc;

ebean-core/src/main/java/io/ebeaninternal/server/loadcontext/DLoadBeanContext.java

@@ -17,6 +17,8 @@ import io.ebeaninternal.server.querydefn.OrmQueryProperties;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Set;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReentrantLock;
 
 /**
  * ToOne bean load context.
@@ -86,11 +88,11 @@ class DLoadBeanContext extends DLoadBaseContext implements LoadBeanContext {
 
   @Override
   public void loadSecondaryQuery(OrmQueryRequest<?> parentRequest, boolean forEach) {
-
     if (!queryFetch) {
       throw new IllegalStateException("Not expecting loadSecondaryQuery() to be called?");
     }
-    synchronized (this) {
+    lock.lock();
+    try {
       if (bufferList != null) {
         for (LoadBuffer loadBuffer : bufferList) {
           if (!loadBuffer.list.isEmpty()) {
@@ -108,6 +110,8 @@ class DLoadBeanContext extends DLoadBaseContext implements LoadBeanContext {
           }
         }
       }
+    } finally {
+      lock.unlock();
     }
   }
 
@@ -116,6 +120,7 @@ class DLoadBeanContext extends DLoadBaseContext implements LoadBeanContext {
    */
   static class LoadBuffer implements BeanLoader, LoadBeanBuffer {
 
+    private final ReentrantLock bufferLock = new ReentrantLock(false);
     private final DLoadBeanContext context;
     private final int batchSize;
     private final List<EntityBeanIntercept> list;
@@ -127,6 +132,12 @@ class DLoadBeanContext extends DLoadBaseContext implements LoadBeanContext {
       this.list = new ArrayList<>(batchSize);
     }
 
+    @Override
+    public Lock lock() {
+      bufferLock.lock();
+      return bufferLock;
+    }
+
     @Override
     public int getBatchSize() {
       return batchSize;
@@ -182,7 +193,7 @@ class DLoadBeanContext extends DLoadBaseContext implements LoadBeanContext {
 
     @Override
     public void loadBean(EntityBeanIntercept ebi) {
-      // A synchronized (this) is effectively held by EntityBeanIntercept.loadBean()
+      // A lock is effectively held by EntityBeanIntercept.loadBean()
       if (context.desc.lazyLoadMany(ebi, context)) {
         // lazy load property was a Many
         return;

ebean-core/src/main/java/io/ebeaninternal/server/loadcontext/DLoadManyContext.java

@@ -16,6 +16,7 @@ import io.ebeaninternal.server.querydefn.OrmQueryProperties;
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.concurrent.locks.ReentrantLock;
 
 /**
  * ToMany bean load context.
@@ -94,11 +95,11 @@ class DLoadManyContext extends DLoadBaseContext implements LoadManyContext {
 
   @Override
   public void loadSecondaryQuery(OrmQueryRequest<?> parentRequest, boolean forEach) {
-
     if (!queryFetch) {
       throw new IllegalStateException("Not expecting loadSecondaryQuery() to be called?");
     }
-    synchronized (this) {
+    lock.lock();
+    try {
       if (bufferList != null) {
         for (LoadBuffer loadBuffer : bufferList) {
           if (!loadBuffer.list.isEmpty()) {
@@ -118,6 +119,8 @@ class DLoadManyContext extends DLoadBaseContext implements LoadManyContext {
           this.bufferList = null;
         }
       }
+    } finally {
+      lock.unlock();
     }
   }
 
@@ -127,6 +130,7 @@ class DLoadManyContext extends DLoadBaseContext implements LoadManyContext {
    */
   static class LoadBuffer implements BeanCollectionLoader, LoadManyBuffer {
 
+    private final ReentrantLock lock = new ReentrantLock(false);
     private final PersistenceContext persistenceContext;
     private final DLoadManyContext context;
     private final int batchSize;
@@ -208,7 +212,8 @@ class DLoadManyContext extends DLoadBaseContext implements LoadManyContext {
     @Override
     public void loadMany(BeanCollection<?> bc, boolean onlyIds) {
 
-      synchronized (this) {
+      lock.lock();
+      try {
         boolean useCache = !onlyIds && context.hitCache && context.property.isUseCache();
         if (useCache) {
           EntityBean ownerBean = bc.getOwnerBean();
@@ -231,6 +236,8 @@ class DLoadManyContext extends DLoadBaseContext implements LoadManyContext {
 
         LoadManyRequest req = new LoadManyRequest(this, onlyIds, useCache);
         context.parent.getEbeanServer().loadMany(req);
+      } finally {
+        lock.unlock();
       }
     }
 

ebean-core/src/main/java/io/ebeaninternal/server/query/CQuery.java

@@ -39,6 +39,7 @@ import java.util.List;
 import java.util.Map;
 import java.util.NoSuchElementException;
 import java.util.Set;
+import java.util.concurrent.locks.ReentrantLock;
 
 /**
  * An object that represents a SqlSelect statement.
@@ -58,6 +59,8 @@ public class CQuery<T> implements DbReadContext, CancelableQuery, SpiProfileTran
 
   private static final CQueryCollectionAddNoop NOOP_ADD = new CQueryCollectionAddNoop();
 
+  private final ReentrantLock lock = new ReentrantLock(false);
+
   /**
    * The resultSet rows read.
    */
@@ -288,7 +291,8 @@ public class CQuery<T> implements DbReadContext, CancelableQuery, SpiProfileTran
 
   @Override
   public void cancel() {
-    synchronized (this) {
+    lock.lock();
+    try {
       this.cancelled = true;
       if (pstmt != null) {
         try {
@@ -298,6 +302,8 @@ public class CQuery<T> implements DbReadContext, CancelableQuery, SpiProfileTran
           throw new PersistenceException(msg, e);
         }
       }
+    } finally {
+      lock.unlock();
     }
   }
 
@@ -326,8 +332,8 @@ public class CQuery<T> implements DbReadContext, CancelableQuery, SpiProfileTran
   }
 
   ResultSet prepareResultSet(boolean forwardOnlyHint) throws SQLException {
-
-    synchronized (this) {
+    lock.lock();
+    try {
       if (cancelled || query.isCancelled()) {
         // cancelled before we started
         cancelled = true;
@@ -370,6 +376,8 @@ public class CQuery<T> implements DbReadContext, CancelableQuery, SpiProfileTran
 
       // executeQuery
       return pstmt.executeQuery();
+    } finally {
+      lock.unlock();
     }
   }
 
@@ -524,8 +532,8 @@ public class CQuery<T> implements DbReadContext, CancelableQuery, SpiProfileTran
   }
 
   boolean hasNext() throws SQLException {
-
-    synchronized (this) {
+    lock.lock();
+    try {
       if (noMoreRows || cancelled) {
         return false;
       }
@@ -534,6 +542,8 @@ public class CQuery<T> implements DbReadContext, CancelableQuery, SpiProfileTran
       }
       hasNextCache = readNextBean();
       return hasNextCache;
+    } finally {
+      lock.unlock();
     }
   }
 

ebean-core/src/main/java/io/ebeaninternal/server/query/CQueryBindCapture.java

@@ -5,10 +5,13 @@ import io.ebeaninternal.api.SpiQueryBindCapture;
 import io.ebeaninternal.api.SpiQueryPlan;
 import io.ebeaninternal.server.type.bindcapture.BindCapture;
 
+import java.util.concurrent.locks.ReentrantLock;
+
 class CQueryBindCapture implements SpiQueryBindCapture {
 
   private static final double multiplier = 1.3d;
 
+  private final ReentrantLock lock = new ReentrantLock(false);
   private final CQueryPlanManager manager;
   private final SpiQueryPlan queryPlan;
 
@@ -35,13 +38,16 @@ class CQueryBindCapture implements SpiQueryBindCapture {
 
   @Override
   public void setBind(BindCapture bindCapture, long queryTimeMicros, long startNanos) {
-    synchronized (this) {
+    lock.lock();
+    try {
       this.thresholdMicros = Math.round(queryTimeMicros * multiplier);
       this.captureCount++;
       this.bindCapture = bindCapture;
       this.queryTimeMicros = queryTimeMicros;
       lastBindCapture = System.currentTimeMillis();
       manager.notifyBindCapture(this, startNanos);
+    } finally {
+      lock.unlock();
     }
   }
 

ebean-core/src/main/java/io/ebeaninternal/server/query/LimitOffsetPagedList.java

@@ -1,31 +1,29 @@
 package io.ebeaninternal.server.query;
 
 import io.ebean.PagedList;
-import io.ebeaninternal.api.Monitor;
 import io.ebeaninternal.api.SpiEbeanServer;
 import io.ebeaninternal.api.SpiQuery;
 
 import javax.persistence.PersistenceException;
 import java.util.List;
 import java.util.concurrent.Future;
+import java.util.concurrent.locks.ReentrantLock;
 
 /**
  * PagedList implementation based on limit offset types of queries.
- *
- * @param <T> the entity bean type
  */
 public class LimitOffsetPagedList<T> implements PagedList<T> {
 
   private final transient SpiEbeanServer server;
 
+  private final transient ReentrantLock lock = new ReentrantLock(false);
+
   private final SpiQuery<T> query;
 
   private final int firstRow;
 
   private final int maxRows;
 
-  private final Monitor monitor = new Monitor();
-
   private int foregroundTotalRowCount = -1;
 
   private Future<Integer> futureRowCount;
@@ -49,21 +47,27 @@ public class LimitOffsetPagedList<T> implements PagedList<T> {
 
   @Override
   public Future<Integer> getFutureCount() {
-    synchronized (monitor) {
+    lock.lock();
+    try {
       if (futureRowCount == null) {
         futureRowCount = server.findFutureCount(query, null);
       }
       return futureRowCount;
+    } finally {
+      lock.unlock();
     }
   }
 
   @Override
   public List<T> getList() {
-    synchronized (monitor) {
+    lock.lock();
+    try {
       if (list == null) {
         list = server.findList(query, null);
       }
       return list;
+    } finally {
+      lock.unlock();
     }
   }
 
@@ -77,7 +81,6 @@ public class LimitOffsetPagedList<T> implements PagedList<T> {
 
   @Override
   public int getTotalPageCount() {
-
     int rowCount = getTotalCount();
     if (rowCount == 0) {
       return 0;
@@ -88,7 +91,8 @@ public class LimitOffsetPagedList<T> implements PagedList<T> {
 
   @Override
   public int getTotalCount() {
-    synchronized (monitor) {
+    lock.lock();
+    try {
       if (futureRowCount != null) {
         try {
           // background query already initiated so get it with a wait
@@ -103,6 +107,8 @@ public class LimitOffsetPagedList<T> implements PagedList<T> {
       // just using foreground thread
       foregroundTotalRowCount = server.findCount(query, null);
       return foregroundTotalRowCount;
+    } finally {
+      lock.unlock();
     }
   }
 
@@ -123,11 +129,9 @@ public class LimitOffsetPagedList<T> implements PagedList<T> {
 
   @Override
   public String getDisplayXtoYofZ(String to, String of) {
-
     int first = firstRow + 1;
     int last = firstRow + getList().size();
     int total = getTotalCount();
-
     return first + to + last + of + total;
   }
 

ebean-core/src/main/java/io/ebeaninternal/server/querydefn/DefaultOrmQuery.java

@@ -71,6 +71,7 @@ import java.util.List;
 import java.util.Map;
 import java.util.Optional;
 import java.util.Set;
+import java.util.concurrent.locks.ReentrantLock;
 import java.util.function.Consumer;
 import java.util.function.Predicate;
 import java.util.stream.Stream;
@@ -88,6 +89,8 @@ public class DefaultOrmQuery<T> implements SpiQuery<T> {
 
   private static final FetchConfig FETCH_LAZY = new FetchConfig().lazy();
 
+  private final ReentrantLock lock = new ReentrantLock(false);
+
   private final Class<T> beanType;
 
   private final ExpressionFactory expressionFactory;
@@ -1992,8 +1995,11 @@ public class DefaultOrmQuery<T> implements SpiQuery<T> {
 
   @Override
   public void setCancelableQuery(CancelableQuery cancelableQuery) {
-    synchronized (this) {
+    lock.lock();
+    try {
       this.cancelableQuery = cancelableQuery;
+    } finally {
+      lock.unlock();
     }
   }
 
@@ -2026,18 +2032,24 @@ public class DefaultOrmQuery<T> implements SpiQuery<T> {
 
   @Override
   public void cancel() {
-    synchronized (this) {
+    lock.lock();
+    try {
       cancelled = true;
       if (cancelableQuery != null) {
         cancelableQuery.cancel();
       }
+    } finally {
+      lock.unlock();
     }
   }
 
   @Override
   public boolean isCancelled() {
-    synchronized (this) {
+    lock.lock();
+    try {
       return cancelled;
+    } finally {
+      lock.unlock();
     }
   }
 

ebean-core/src/main/java/io/ebeaninternal/server/transaction/DefaultPersistenceContext.java

@@ -1,12 +1,12 @@
 package io.ebeaninternal.server.transaction;
 
 import io.ebean.bean.PersistenceContext;
-import io.ebeaninternal.api.Monitor;
 
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Map;
 import java.util.Set;
+import java.util.concurrent.locks.ReentrantLock;
 
 /**
  * Default implementation of PersistenceContext.
@@ -32,7 +32,7 @@ public final class DefaultPersistenceContext implements PersistenceContext {
    */
   private final HashMap<Class<?>, ClassContext> typeCache = new HashMap<>();
 
-  private final Monitor monitor = new Monitor();
+  private final ReentrantLock lock = new ReentrantLock(false);
 
   private int putCount;
 
@@ -68,7 +68,8 @@ public final class DefaultPersistenceContext implements PersistenceContext {
   }
 
   public boolean resetLimit() {
-    synchronized (monitor) {
+    lock.lock();
+    try {
       if (putCount < 100) {
         return false;
       }
@@ -80,6 +81,8 @@ public final class DefaultPersistenceContext implements PersistenceContext {
       }
       // checking after another 100 puts
       return false;
+    } finally {
+      lock.unlock();
     }
   }
 
@@ -88,17 +91,23 @@ public final class DefaultPersistenceContext implements PersistenceContext {
    */
   @Override
   public void put(Class<?> rootType, Object id, Object bean) {
-    synchronized (monitor) {
+    lock.lock();
+    try {
       putCount++;
       getClassContext(rootType).put(id, bean);
+    } finally {
+      lock.unlock();
     }
   }
 
   @Override
   public Object putIfAbsent(Class<?> rootType, Object id, Object bean) {
-    synchronized (monitor) {
+    lock.lock();
+    try {
       putCount++;
       return getClassContext(rootType).putIfAbsent(id, bean);
+    } finally {
+      lock.unlock();
     }
   }
 
@@ -107,15 +116,21 @@ public final class DefaultPersistenceContext implements PersistenceContext {
    */
   @Override
   public Object get(Class<?> rootType, Object id) {
-    synchronized (monitor) {
+    lock.lock();
+    try {
       return getClassContext(rootType).get(id);
+    } finally {
+      lock.unlock();
     }
   }
 
   @Override
   public WithOption getWithOption(Class<?> rootType, Object id) {
-    synchronized (monitor) {
+    lock.lock();
+    try {
       return getClassContext(rootType).getWithOption(id);
+    } finally {
+      lock.unlock();
     }
   }
 
@@ -124,9 +139,12 @@ public final class DefaultPersistenceContext implements PersistenceContext {
    */
   @Override
   public int size(Class<?> rootType) {
-    synchronized (monitor) {
+    lock.lock();
+    try {
       ClassContext classMap = typeCache.get(rootType);
       return classMap == null ? 0 : classMap.size();
+    } finally {
+      lock.unlock();
     }
   }
 
@@ -135,45 +153,60 @@ public final class DefaultPersistenceContext implements PersistenceContext {
    */
   @Override
   public void clear() {
-    synchronized (monitor) {
+    lock.lock();
+    try {
       typeCache.clear();
+    } finally {
+      lock.unlock();
     }
   }
 
   @Override
   public void clear(Class<?> rootType) {
-    synchronized (monitor) {
+    lock.lock();
+    try {
       ClassContext classMap = typeCache.get(rootType);
       if (classMap != null) {
         classMap.clear();
       }
+    } finally {
+      lock.unlock();
     }
   }
 
   @Override
   public void deleted(Class<?> rootType, Object id) {
-    synchronized (monitor) {
+    lock.lock();
+    try {
       ClassContext classMap = typeCache.get(rootType);
       if (classMap != null && id != null) {
         classMap.deleted(id);
       }
+    } finally {
+      lock.unlock();
     }
   }
 
   @Override
   public void clear(Class<?> rootType, Object id) {
-    synchronized (monitor) {
+    lock.lock();
+    try {
       ClassContext classMap = typeCache.get(rootType);
       if (classMap != null && id != null) {
         classMap.remove(id);
       }
+    } finally {
+      lock.unlock();
     }
   }
 
   @Override
   public String toString() {
-    synchronized (monitor) {
+    lock.lock();
+    try {
       return typeCache.toString();
+    } finally {
+      lock.unlock();
     }
   }
 

ebean-core/src/main/java/io/ebeaninternal/server/transaction/DefaultProfileHandler.java

@@ -21,6 +21,7 @@ import java.util.concurrent.ConcurrentLinkedQueue;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.concurrent.TimeUnit;
+import java.util.concurrent.locks.ReentrantLock;
 
 import static java.time.temporal.ChronoField.DAY_OF_MONTH;
 import static java.time.temporal.ChronoField.HOUR_OF_DAY;
@@ -65,6 +66,8 @@ public class DefaultProfileHandler implements SpiProfileHandler, Plugin {
 
   private final ExecutorService executor;
 
+  private final ReentrantLock lock = new ReentrantLock(false);
+
   private final File dir;
 
   private final long minMicros;
@@ -117,7 +120,8 @@ public class DefaultProfileHandler implements SpiProfileHandler, Plugin {
   }
 
   private void flushCurrentFile() {
-    synchronized (this) {
+    lock.lock();
+    try {
       if (out != null) {
         try {
           out.close();
@@ -126,6 +130,8 @@ public class DefaultProfileHandler implements SpiProfileHandler, Plugin {
           log.error("Failed to flush and close transaction profiling file ", e);
         }
       }
+    } finally {
+      lock.unlock();
     }
   }
 
@@ -133,7 +139,8 @@ public class DefaultProfileHandler implements SpiProfileHandler, Plugin {
    * Move to the next file to write to.
    */
   private void incrementFile() {
-    synchronized (this) {
+    lock.lock();
+    try {
       flushCurrentFile();
       try {
         String now = DTF.format(LocalDateTime.now());
@@ -142,6 +149,8 @@ public class DefaultProfileHandler implements SpiProfileHandler, Plugin {
       } catch (IOException e) {
         log.error("Not expected", e);
       }
+    } finally {
+      lock.unlock();
     }
   }