ZOOKEEPER-3582: refactor the async api call to lambda style

Author: ZWShuai91 <17610028856@163.com>

Reviewers: eolivelli@apache.org, andor@apache.org

Closes #1142 from ZWShuai91/ZOOKEEPER-3582

zookeeper-server/src/main/java/org/apache/zookeeper/cli/LsCommand.java

@@ -25,7 +25,6 @@ import org.apache.commons.cli.Options;
 import org.apache.commons.cli.ParseException;
 import org.apache.commons.cli.Parser;
 import org.apache.commons.cli.PosixParser;
-import org.apache.zookeeper.AsyncCallback.StringCallback;
 import org.apache.zookeeper.KeeperException;
 import org.apache.zookeeper.ZKUtil;
 import org.apache.zookeeper.data.Stat;
@@ -102,12 +101,7 @@ public class LsCommand extends CliCommand {
         boolean recursive = cl.hasOption("R");
         try {
             if (recursive) {
-                ZKUtil.visitSubTreeDFS(zk, path, watch, new StringCallback() {
-                    @Override
-                    public void processResult(int rc, String path, Object ctx, String name) {
-                        out.println(path);
-                    }
-                });
+                ZKUtil.visitSubTreeDFS(zk, path, watch, (rc, path1, ctx, name) -> out.println(path1));
             } else {
                 Stat stat = withStat ? new Stat() : null;
                 List<String> children = zk.getChildren(path, watch, stat);

zookeeper-server/src/main/java/org/apache/zookeeper/cli/SetAclCommand.java

@@ -24,7 +24,6 @@ import org.apache.commons.cli.Options;
 import org.apache.commons.cli.ParseException;
 import org.apache.commons.cli.Parser;
 import org.apache.commons.cli.PosixParser;
-import org.apache.zookeeper.AsyncCallback.StringCallback;
 import org.apache.zookeeper.KeeperException;
 import org.apache.zookeeper.ZKUtil;
 import org.apache.zookeeper.data.ACL;
@@ -81,14 +80,11 @@ public class SetAclCommand extends CliCommand {
         }
         try {
             if (cl.hasOption("R")) {
-                ZKUtil.visitSubTreeDFS(zk, path, false, new StringCallback() {
-                    @Override
-                    public void processResult(int rc, String p, Object ctx, String name) {
-                        try {
-                            zk.setACL(p, acl, version);
-                        } catch (KeeperException | InterruptedException e) {
-                            out.print(e.getMessage());
-                        }
+                ZKUtil.visitSubTreeDFS(zk, path, false, (rc, p, ctx, name) -> {
+                    try {
+                        zk.setACL(p, acl, version);
+                    } catch (KeeperException | InterruptedException e) {
+                        out.print(e.getMessage());
                     }
                 });
             } else {

zookeeper-server/src/main/java/org/apache/zookeeper/cli/SetQuotaCommand.java

@@ -27,7 +27,6 @@ import org.apache.commons.cli.Options;
 import org.apache.commons.cli.ParseException;
 import org.apache.commons.cli.Parser;
 import org.apache.commons.cli.PosixParser;
-import org.apache.zookeeper.AsyncCallback;
 import org.apache.zookeeper.CreateMode;
 import org.apache.zookeeper.KeeperException;
 import org.apache.zookeeper.Quotas;
@@ -194,27 +193,23 @@ public class SetQuotaCommand extends CliCommand {
         String realPath = Quotas.quotaZookeeper + path;
 
         try {
-            ZKUtil.visitSubTreeDFS(zk, realPath, false, new AsyncCallback.StringCallback() {
-
-                @Override
-                public void processResult(int rc, String quotaPath, Object ctx, String name) {
-                    List<String> children = new ArrayList<>();
-                    try {
-                        children = zk.getChildren(quotaPath, false);
-                    } catch (KeeperException.NoNodeException ne) {
-                        LOG.debug("child removed during quota check", ne);
-                        return;
-                    } catch (InterruptedException | KeeperException e) {
-                        e.printStackTrace();
-                    }
+            ZKUtil.visitSubTreeDFS(zk, realPath, false, (rc, quotaPath, ctx, name) -> {
+                List<String> children = new ArrayList<>();
+                try {
+                    children = zk.getChildren(quotaPath, false);
+                } catch (KeeperException.NoNodeException ne) {
+                    LOG.debug("child removed during quota check", ne);
+                    return;
+                } catch (InterruptedException | KeeperException e) {
+                    e.printStackTrace();
+                }
 
-                    if (children.size() == 0) {
-                        return;
-                    }
-                    for (String child : children) {
-                        if (!quotaPath.equals(Quotas.quotaZookeeper + path) && Quotas.limitNode.equals(child)) {
-                            throw new IllegalArgumentException(path + " has a child " + quotaPath.substring(Quotas.quotaZookeeper.length()) + " which has a quota");
-                        }
+                if (children.size() == 0) {
+                    return;
+                }
+                for (String child : children) {
+                    if (!quotaPath.equals(Quotas.quotaZookeeper + path) && Quotas.limitNode.equals(child)) {
+                        throw new IllegalArgumentException(path + " has a child " + quotaPath.substring(Quotas.quotaZookeeper.length()) + " which has a quota");
                     }
                 }
             });

zookeeper-server/src/main/java/org/apache/zookeeper/cli/SyncCommand.java

@@ -26,7 +26,6 @@ import org.apache.commons.cli.Options;
 import org.apache.commons.cli.ParseException;
 import org.apache.commons.cli.Parser;
 import org.apache.commons.cli.PosixParser;
-import org.apache.zookeeper.AsyncCallback;
 
 /**
  * sync command for cli
@@ -64,11 +63,7 @@ public class SyncCommand extends CliCommand {
         CompletableFuture<Integer> cf = new CompletableFuture<>();
 
         try {
-            zk.sync(path, new AsyncCallback.VoidCallback() {
-                public void processResult(int rc, String path, Object ctx) {
-                    cf.complete(rc);
-                }
-            }, null);
+            zk.sync(path, (rc, path1, ctx) -> cf.complete(rc), null);
 
             int resultCode = cf.get(SYNC_TIMEOUT, TimeUnit.MILLISECONDS);
             if (resultCode == 0) {

zookeeper-server/src/test/java/org/apache/zookeeper/GetAllChildrenNumberTest.java

@@ -74,15 +74,12 @@ public class GetAllChildrenNumberTest extends ClientBase {
 
         final CountDownLatch doneProcessing = new CountDownLatch(1);
 
-        zk.getAllChildrenNumber("/", new AsyncCallback.AllChildrenNumberCallback() {
-            @Override
-            public void processResult(int rc, String path, Object ctx, int number) {
-                if (path == null) {
-                    fail((String.format("the path of getAllChildrenNumber was null.")));
-                }
-                assertEquals(13, number);
-                doneProcessing.countDown();
+        zk.getAllChildrenNumber("/", (rc, path, ctx, number) -> {
+            if (path == null) {
+                fail((String.format("the path of getAllChildrenNumber was null.")));
             }
+            assertEquals(13, number);
+            doneProcessing.countDown();
         }, null);
         long waitForCallbackSecs = 2L;
         if (!doneProcessing.await(waitForCallbackSecs, TimeUnit.SECONDS)) {

zookeeper-server/src/test/java/org/apache/zookeeper/GetEphemeralsTest.java

@@ -80,23 +80,20 @@ public class GetEphemeralsTest extends ClientBase {
 
         final CountDownLatch doneProcessing = new CountDownLatch(1);
         final List<String> unexpectedBehavior = new ArrayList<String>();
-        zk.getEphemerals(new AsyncCallback.EphemeralsCallback() {
-            @Override
-            public void processResult(int rc, Object ctx, List<String> paths) {
-                if (paths == null) {
-                    unexpectedBehavior.add(String.format("Expected ephemeral count for"
-                                                                 + " allPaths to be %d but was null", expected.length));
-                } else if (paths.size() != expected.length) {
-                    unexpectedBehavior.add(String.format("Expected ephemeral count for allPaths to be %d but was %d", expected.length, paths.size()));
-                }
-                for (int i = 0; i < expected.length; i++) {
-                    String path = expected[i];
-                    if (!paths.contains(path)) {
-                        unexpectedBehavior.add(String.format("Path=%s exists in getEphemerals list ", path));
-                    }
+        zk.getEphemerals((rc, ctx, paths) -> {
+            if (paths == null) {
+                unexpectedBehavior.add(String.format("Expected ephemeral count for"
+                                                             + " allPaths to be %d but was null", expected.length));
+            } else if (paths.size() != expected.length) {
+                unexpectedBehavior.add(String.format("Expected ephemeral count for allPaths to be %d but was %d", expected.length, paths.size()));
+            }
+            for (int i = 0; i < expected.length; i++) {
+                String path = expected[i];
+                if (!paths.contains(path)) {
+                    unexpectedBehavior.add(String.format("Path=%s exists in getEphemerals list ", path));
                 }
-                doneProcessing.countDown();
             }
+            doneProcessing.countDown();
         }, null);
         long waitForCallbackSecs = 2L;
         if (!doneProcessing.await(waitForCallbackSecs, TimeUnit.SECONDS)) {
@@ -112,23 +109,20 @@ public class GetEphemeralsTest extends ClientBase {
         final CountDownLatch doneProcessing = new CountDownLatch(1);
         final String checkPath = BASE + "0";
         final List<String> unexpectedBehavior = new ArrayList<String>();
-        zk.getEphemerals(checkPath, new AsyncCallback.EphemeralsCallback() {
-            @Override
-            public void processResult(int rc, Object ctx, List<String> paths) {
-                if (paths == null) {
-                    unexpectedBehavior.add(String.format("Expected ephemeral count for %s to be %d but was null", checkPath, expected.length));
-                } else if (paths.size() != EPHEMERAL_CNT) {
-                    unexpectedBehavior.add(String.format("Expected ephemeral count for %s to be %d but was %d", checkPath, EPHEMERAL_CNT, paths.size()));
-                }
-                for (int i = 0; i < EPHEMERAL_CNT; i++) {
-                    String path = expected[i];
-                    if (!paths.contains(path)) {
-                        unexpectedBehavior.add(String.format("Expected path=%s didn't exist "
-                                                                     + "in getEphemerals list.", path));
-                    }
+        zk.getEphemerals(checkPath, (rc, ctx, paths) -> {
+            if (paths == null) {
+                unexpectedBehavior.add(String.format("Expected ephemeral count for %s to be %d but was null", checkPath, expected.length));
+            } else if (paths.size() != EPHEMERAL_CNT) {
+                unexpectedBehavior.add(String.format("Expected ephemeral count for %s to be %d but was %d", checkPath, EPHEMERAL_CNT, paths.size()));
+            }
+            for (int i = 0; i < EPHEMERAL_CNT; i++) {
+                String path = expected[i];
+                if (!paths.contains(path)) {
+                    unexpectedBehavior.add(String.format("Expected path=%s didn't exist "
+                                                                 + "in getEphemerals list.", path));
                 }
-                doneProcessing.countDown();
             }
+            doneProcessing.countDown();
         }, null);
         long waitForCallbackSecs = 2L;
         if (!doneProcessing.await(waitForCallbackSecs, TimeUnit.SECONDS)) {
@@ -144,16 +138,13 @@ public class GetEphemeralsTest extends ClientBase {
         final String checkPath = "/unknownPath";
         final int expectedSize = 0;
         final List<String> unexpectedBehavior = new ArrayList<String>();
-        zk.getEphemerals(checkPath, new AsyncCallback.EphemeralsCallback() {
-            @Override
-            public void processResult(int rc, Object ctx, List<String> paths) {
-                if (paths == null) {
-                    unexpectedBehavior.add(String.format("Expected ephemeral count for %s to be %d but was null", checkPath, expectedSize));
-                } else if (paths.size() != expectedSize) {
-                    unexpectedBehavior.add(String.format("Expected ephemeral count for %s to be %d but was %d", checkPath, expectedSize, paths.size()));
-                }
-                doneProcessing.countDown();
+        zk.getEphemerals(checkPath, (rc, ctx, paths) -> {
+            if (paths == null) {
+                unexpectedBehavior.add(String.format("Expected ephemeral count for %s to be %d but was null", checkPath, expectedSize));
+            } else if (paths.size() != expectedSize) {
+                unexpectedBehavior.add(String.format("Expected ephemeral count for %s to be %d but was %d", checkPath, expectedSize, paths.size()));
             }
+            doneProcessing.countDown();
         }, null);
         long waitForCallbackSecs = 2L;
         if (!doneProcessing.await(waitForCallbackSecs, TimeUnit.SECONDS)) {

zookeeper-server/src/test/java/org/apache/zookeeper/server/CreateContainerTest.java

@@ -155,12 +155,9 @@ public class CreateContainerTest extends ClientBase {
     @Test(timeout = 30000)
     public void testSimpleDeletionAsync() throws KeeperException, InterruptedException {
         final CountDownLatch latch = new CountDownLatch(1);
-        AsyncCallback.Create2Callback cb = new AsyncCallback.Create2Callback() {
-            @Override
-            public void processResult(int rc, String path, Object ctx, String name, Stat stat) {
-                assertEquals(ctx, "context");
-                latch.countDown();
-            }
+        AsyncCallback.Create2Callback cb = (rc, path, ctx, name, stat) -> {
+            assertEquals(ctx, "context");
+            latch.countDown();
         };
         zk.create("/foo", new byte[0], ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.CONTAINER, cb, "context");
         assertTrue(latch.await(5, TimeUnit.SECONDS));

zookeeper-server/src/test/java/org/apache/zookeeper/server/CreateTTLTest.java

@@ -131,11 +131,8 @@ public class CreateTTLTest extends ClientBase {
 
     @Test
     public void testCreateAsync() throws KeeperException, InterruptedException {
-        AsyncCallback.Create2Callback callback = new AsyncCallback.Create2Callback() {
-            @Override
-            public void processResult(int rc, String path, Object ctx, String name, Stat stat) {
-                // NOP
-            }
+        AsyncCallback.Create2Callback callback = (rc, path, ctx, name, stat) -> {
+            // NOP
         };
         zk.create("/foo", new byte[0], ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT_WITH_TTL, callback, null, 100);
 
@@ -212,11 +209,8 @@ public class CreateTTLTest extends ClientBase {
         }
 
         for (CreateMode createMode : CreateMode.values()) {
-            AsyncCallback.Create2Callback callback = new AsyncCallback.Create2Callback() {
-                @Override
-                public void processResult(int rc, String path, Object ctx, String name, Stat stat) {
-                    // NOP
-                }
+            AsyncCallback.Create2Callback callback = (rc, path, ctx, name, stat) -> {
+                // NOP
             };
             try {
                 zk.create("/foo", new byte[0], ZooDefs.Ids.OPEN_ACL_UNSAFE, createMode, callback, null, createMode.isTTL() ? 0 : 100);

zookeeper-server/src/test/java/org/apache/zookeeper/server/quorum/CloseSessionTxnTest.java

@@ -20,7 +20,6 @@ package org.apache.zookeeper.server.quorum;
 
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.TimeUnit;
-import org.apache.zookeeper.AsyncCallback;
 import org.apache.zookeeper.CreateMode;
 import org.apache.zookeeper.ZooDefs.Ids;
 import org.apache.zookeeper.ZooKeeper.States;
@@ -89,12 +88,7 @@ public class CloseSessionTxnTest extends QuorumPeerTestBase {
         // 4. verify the ephemeral node is gone
         for (int i = 0; i < numServers; i++) {
             final CountDownLatch syncedLatch = new CountDownLatch(1);
-            servers.zk[i].sync(path, new AsyncCallback.VoidCallback() {
-                @Override
-                public void processResult(int rc, String path, Object ctx) {
-                    syncedLatch.countDown();
-                }
-            }, null);
+            servers.zk[i].sync(path, (rc, path1, ctx) -> syncedLatch.countDown(), null);
             Assert.assertTrue(syncedLatch.await(3, TimeUnit.SECONDS));
             Assert.assertNull(servers.zk[i].exists(path, false));
         }

zookeeper-server/src/test/java/org/apache/zookeeper/server/quorum/QuorumPeerMainTest.java

@@ -51,7 +51,6 @@ import org.apache.log4j.Level;
 import org.apache.log4j.Logger;
 import org.apache.log4j.PatternLayout;
 import org.apache.log4j.WriterAppender;
-import org.apache.zookeeper.AsyncCallback;
 import org.apache.zookeeper.CreateMode;
 import org.apache.zookeeper.KeeperException;
 import org.apache.zookeeper.PortAssignment;
@@ -61,7 +60,6 @@ import org.apache.zookeeper.ZooKeeper;
 import org.apache.zookeeper.ZooKeeper.States;
 import org.apache.zookeeper.common.Time;
 import org.apache.zookeeper.common.X509Exception;
-import org.apache.zookeeper.data.Stat;
 import org.apache.zookeeper.metrics.BaseTestMetricsProvider;
 import org.apache.zookeeper.metrics.impl.NullMetricsProvider;
 import org.apache.zookeeper.server.persistence.FileTxnSnapLog;
@@ -1146,9 +1144,7 @@ public class QuorumPeerMainTest extends QuorumPeerTestBase {
                     // use async, otherwise it will block the logLock in
                     // ZKDatabase and the setData request will timeout
                     try {
-                        leaderZk.setData(nodePath, value.getBytes(), -1, new AsyncCallback.StatCallback() {
-                            public void processResult(int rc, String path, Object ctx, Stat stat) {
-                            }
+                        leaderZk.setData(nodePath, value.getBytes(), -1, (rc, path, ctx, stat) -> {
                         }, null);
                         // wait for the setData txn being populated
                         Thread.sleep(1000);

zookeeper-server/src/test/java/org/apache/zookeeper/test/ClientTest.java

@@ -32,7 +32,6 @@ import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.LinkedBlockingQueue;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicInteger;
-import org.apache.zookeeper.AsyncCallback;
 import org.apache.zookeeper.CreateMode;
 import org.apache.zookeeper.KeeperException;
 import org.apache.zookeeper.KeeperException.Code;
@@ -832,12 +831,9 @@ public class ClientTest extends ClientBase {
             for (int i = 0; i < 20; ++i) {
                 final CountDownLatch latch = new CountDownLatch(1);
                 final AtomicInteger rc = new AtomicInteger(0);
-                zk.setData("/testnode", "".getBytes(), -1, new AsyncCallback.StatCallback() {
-                    @Override
-                    public void processResult(int retcode, String path, Object ctx, Stat stat) {
-                        rc.set(retcode);
-                        latch.countDown();
-                    }
+                zk.setData("/testnode", "".getBytes(), -1, (retcode, path, ctx, stat) -> {
+                    rc.set(retcode);
+                    latch.countDown();
                 }, null);
                 assertTrue("setData should complete within 5s", latch.await(zk.getSessionTimeout(), TimeUnit.MILLISECONDS));
                 assertEquals("setData should have succeeded", Code.OK.intValue(), rc.get());

zookeeper-server/src/test/java/org/apache/zookeeper/test/FollowerResyncConcurrencyTest.java

@@ -33,7 +33,6 @@ import java.util.concurrent.TimeUnit;
 import java.util.concurrent.TimeoutException;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicInteger;
-import org.apache.zookeeper.AsyncCallback;
 import org.apache.zookeeper.CreateMode;
 import org.apache.zookeeper.KeeperException;
 import org.apache.zookeeper.TestableZooKeeper;
@@ -242,18 +241,14 @@ public class FollowerResyncConcurrencyTest extends ZKTestCase {
             public void run() {
                 for (int i = 0; i < 3000; i++) {
                     // Here we create 3000 znodes
-                    zk3.create("/mytestfoo", null, ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL_SEQUENTIAL, new AsyncCallback.StringCallback() {
-
-                        @Override
-                        public void processResult(int rc, String path, Object ctx, String name) {
-                            pending.decrementAndGet();
-                            counter.incrementAndGet();
-                            if (rc != 0) {
-                                errors.incrementAndGet();
-                            }
-                            if (counter.get() == 16200) {
-                                sem.release();
-                            }
+                    zk3.create("/mytestfoo", null, ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL_SEQUENTIAL, (rc, path, ctx, name) -> {
+                        pending.decrementAndGet();
+                        counter.incrementAndGet();
+                        if (rc != 0) {
+                            errors.incrementAndGet();
+                        }
+                        if (counter.get() == 16200) {
+                            sem.release();
                         }
                     }, null);
                     pending.incrementAndGet();
@@ -273,18 +268,14 @@ public class FollowerResyncConcurrencyTest extends ZKTestCase {
         // initial data is written.
         for (int i = 0; i < 13000; i++) {
             // Here we create 13000 znodes
-            zk3.create("/mybar", null, ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL_SEQUENTIAL, new AsyncCallback.StringCallback() {
-
-                @Override
-                public void processResult(int rc, String path, Object ctx, String name) {
-                    pending.decrementAndGet();
-                    counter.incrementAndGet();
-                    if (rc != 0) {
-                        errors.incrementAndGet();
-                    }
-                    if (counter.get() == 16200) {
-                        sem.release();
-                    }
+            zk3.create("/mybar", null, ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL_SEQUENTIAL, (rc, path, ctx, name) -> {
+                pending.decrementAndGet();
+                counter.incrementAndGet();
+                if (rc != 0) {
+                    errors.incrementAndGet();
+                }
+                if (counter.get() == 16200) {
+                    sem.release();
                 }
             }, null);
             pending.incrementAndGet();
@@ -314,17 +305,14 @@ public class FollowerResyncConcurrencyTest extends ZKTestCase {
             }
 
             if (i % 50 == 0) {
-                zk2.create("/newbaz", null, ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL_SEQUENTIAL, new AsyncCallback.StringCallback() {
-                    @Override
-                    public void processResult(int rc, String path, Object ctx, String name) {
-                        pending.decrementAndGet();
-                        counter.incrementAndGet();
-                        if (rc != 0) {
-                            errors.incrementAndGet();
-                        }
-                        if (counter.get() == 16200) {
-                            sem.release();
-                        }
+                zk2.create("/newbaz", null, ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL_SEQUENTIAL, (rc, path, ctx, name) -> {
+                    pending.decrementAndGet();
+                    counter.incrementAndGet();
+                    if (rc != 0) {
+                        errors.incrementAndGet();
+                    }
+                    if (counter.get() == 16200) {
+                        sem.release();
                     }
                 }, null);
                 pending.incrementAndGet();
@@ -417,18 +405,14 @@ public class FollowerResyncConcurrencyTest extends ZKTestCase {
                 int inSyncCounter = 0;
                 while (inSyncCounter < 400) {
                     if (runNow.get()) {
-                        zk3.create("/mytestfoo", null, ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL_SEQUENTIAL, new AsyncCallback.StringCallback() {
-
-                            @Override
-                            public void processResult(int rc, String path, Object ctx, String name) {
-                                pending.decrementAndGet();
-                                counter.incrementAndGet();
-                                if (rc != 0) {
-                                    errors.incrementAndGet();
-                                }
-                                if (counter.get() > 7300) {
-                                    sem.release();
-                                }
+                        zk3.create("/mytestfoo", null, ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL_SEQUENTIAL, (rc, path, ctx, name) -> {
+                            pending.decrementAndGet();
+                            counter.incrementAndGet();
+                            if (rc != 0) {
+                                errors.incrementAndGet();
+                            }
+                            if (counter.get() > 7300) {
+                                sem.release();
                             }
                         }, null);
                         pending.incrementAndGet();
@@ -447,18 +431,14 @@ public class FollowerResyncConcurrencyTest extends ZKTestCase {
 
         mytestfooThread.start();
         for (int i = 0; i < 5000; i++) {
-            zk2.create("/mybar", null, ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL_SEQUENTIAL, new AsyncCallback.StringCallback() {
-
-                @Override
-                public void processResult(int rc, String path, Object ctx, String name) {
-                    pending.decrementAndGet();
-                    counter.incrementAndGet();
-                    if (rc != 0) {
-                        errors.incrementAndGet();
-                    }
-                    if (counter.get() > 7300) {
-                        sem.release();
-                    }
+            zk2.create("/mybar", null, ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL_SEQUENTIAL, (rc, path, ctx, name) -> {
+                pending.decrementAndGet();
+                counter.incrementAndGet();
+                if (rc != 0) {
+                    errors.incrementAndGet();
+                }
+                if (counter.get() > 7300) {
+                    sem.release();
                 }
             }, null);
             pending.incrementAndGet();
@@ -479,18 +459,14 @@ public class FollowerResyncConcurrencyTest extends ZKTestCase {
             }
 
             if (i >= 1000 && i % 2 == 0) {
-                zk3.create("/newbaz", null, ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL_SEQUENTIAL, new AsyncCallback.StringCallback() {
-
-                    @Override
-                    public void processResult(int rc, String path, Object ctx, String name) {
-                        pending.decrementAndGet();
-                        counter.incrementAndGet();
-                        if (rc != 0) {
-                            errors.incrementAndGet();
-                        }
-                        if (counter.get() > 7300) {
-                            sem.release();
-                        }
+                zk3.create("/newbaz", null, ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL_SEQUENTIAL, (rc, path, ctx, name) -> {
+                    pending.decrementAndGet();
+                    counter.incrementAndGet();
+                    if (rc != 0) {
+                        errors.incrementAndGet();
+                    }
+                    if (counter.get() > 7300) {
+                        sem.release();
                     }
                 }, null);
                 pending.incrementAndGet();

zookeeper-server/src/test/java/org/apache/zookeeper/test/ObserverMasterTest.java

@@ -45,7 +45,6 @@ import javax.management.MalformedObjectNameException;
 import javax.management.ObjectName;
 import javax.management.ReflectionException;
 import javax.management.RuntimeMBeanException;
-import org.apache.zookeeper.AsyncCallback;
 import org.apache.zookeeper.CreateMode;
 import org.apache.zookeeper.DummyWatcher;
 import org.apache.zookeeper.KeeperException;
@@ -721,15 +720,12 @@ public class ObserverMasterTest extends QuorumPeerTestBase implements Watcher {
             for (int i = 0; i < numTransactions; i++) {
                 final boolean pleaseLog = i % 100 == 0;
                 client.create(root
-                                      + i, "inner thread".getBytes(), Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT, new AsyncCallback.StringCallback() {
-                    @Override
-                    public void processResult(int rc, String path, Object ctx, String name) {
-                        writerLatch.countDown();
-                        if (pleaseLog) {
-                            LOG.info("wrote {}", path);
-                        }
-                    }
-                }, null);
+                                      + i, "inner thread".getBytes(), Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT, (rc, path, ctx, name) -> {
+                                          writerLatch.countDown();
+                                          if (pleaseLog) {
+                                              LOG.info("wrote {}", path);
+                                          }
+                                      }, null);
                 if (pleaseLog) {
                     LOG.info("async wrote {}{}", root, i);
                     if (issueSync) {

zookeeper-server/src/test/java/org/apache/zookeeper/test/QuorumTest.java

@@ -27,7 +27,6 @@ import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.concurrent.TimeoutException;
-import org.apache.zookeeper.AsyncCallback;
 import org.apache.zookeeper.CreateMode;
 import org.apache.zookeeper.DummyWatcher;
 import org.apache.zookeeper.KeeperException;
@@ -39,7 +38,6 @@ import org.apache.zookeeper.ZKTestCase;
 import org.apache.zookeeper.ZooDefs;
 import org.apache.zookeeper.ZooDefs.Ids;
 import org.apache.zookeeper.ZooKeeper;
-import org.apache.zookeeper.data.Stat;
 import org.apache.zookeeper.server.quorum.Leader;
 import org.apache.zookeeper.server.quorum.LearnerHandler;
 import org.apache.zookeeper.test.ClientBase.CountdownWatcher;
@@ -151,12 +149,10 @@ public class QuorumTest extends ZKTestCase {
         }
         assertNotNull(leader);
         for (int i = 0; i < 5000; i++) {
-            zk.setData("/blah/blah", new byte[0], -1, new AsyncCallback.StatCallback() {
-                public void processResult(int rc, String path, Object ctx, Stat stat) {
-                    counter++;
-                    if (rc != 0) {
-                        errors++;
-                    }
+            zk.setData("/blah/blah", new byte[0], -1, (rc, path, ctx, stat) -> {
+                counter++;
+                if (rc != 0) {
+                    errors++;
                 }
             }, null);
         }
@@ -164,12 +160,10 @@ public class QuorumTest extends ZKTestCase {
             f.getSocket().shutdownInput();
         }
         for (int i = 0; i < 5000; i++) {
-            zk.setData("/blah/blah", new byte[0], -1, new AsyncCallback.StatCallback() {
-                public void processResult(int rc, String path, Object ctx, Stat stat) {
-                    counter++;
-                    if (rc != 0) {
-                        errors++;
-                    }
+            zk.setData("/blah/blah", new byte[0], -1, (rc, path, ctx, stat) -> {
+                counter++;
+                if (rc != 0) {
+                    errors++;
                 }
             }, null);
         }
@@ -216,12 +210,10 @@ public class QuorumTest extends ZKTestCase {
             zknew.setData("/", new byte[1], -1);
             final int[] result = new int[1];
             result[0] = Integer.MAX_VALUE;
-            zknew.sync("/", new AsyncCallback.VoidCallback() {
-                public void processResult(int rc, String path, Object ctx) {
-                    synchronized (result) {
-                        result[0] = rc;
-                        result.notify();
-                    }
+            zknew.sync("/", (rc, path, ctx) -> {
+                synchronized (result) {
+                    result[0] = rc;
+                    result.notify();
                 }
             }, null);
             synchronized (result) {

zookeeper-server/src/test/java/org/apache/zookeeper/test/SessionTest.java

@@ -245,12 +245,10 @@ public class SessionTest extends ZKTestCase {
                             + 1)), zk.getSessionId(), zk.getSessionPasswd());
             final int[] result = new int[1];
             result[0] = Integer.MAX_VALUE;
-            zknew.sync("/", new AsyncCallback.VoidCallback() {
-                public void processResult(int rc, String path, Object ctx) {
-                    synchronized (result) {
-                        result[0] = rc;
-                        result.notify();
-                    }
+            zknew.sync("/", (rc, path, ctx) -> {
+                synchronized (result) {
+                    result[0] = rc;
+                    result.notify();
                 }
             }, null);
             synchronized (result) {