sync-examples NullPointerException

[cocktail18]

I got io.vertx.core.VertxException: java.lang.NullPointerException when i run sync-examples

• branch : master
• java sdk: java: 11.0.3
• log:

WARNING: Please consider reporting this to the maintainers of org.codehaus.groovy.vmplugin.v7.Java7$1
WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations
WARNING: All illegal access operations will be denied in a future release
QUASAR WARNING: Quasar Java Agent isn't running. If you're using another instrumentation method you can ignore this message; otherwise, please refer to the Getting Started section in the Quasar documentation.
MLog initialization issue: slf4j found no binding or threatened to use its (dangerously silent) NOPLogger. We consider the slf4j library not found.
Aug 28, 2019 12:18:32 PM com.mchange.v2.log.MLog 
INFO: MLog clients using java 1.4+ standard logging.
Aug 28, 2019 12:18:32 PM com.mchange.v2.c3p0.C3P0Registry 
INFO: Initializing c3p0-0.9.5.4 [built 23-March-2019 23:00:48 -0700; debug? true; trace: 10]
Aug 28, 2019 12:18:32 PM com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource 
INFO: Initializing c3p0 pool... com.mchange.v2.c3p0.ComboPooledDataSource [ acquireIncrement -> 3, acquireRetryAttempts -> 30, acquireRetryDelay -> 1000, autoCommitOnClose -> false, automaticTestTable -> null, breakAfterAcquireFailure -> false, checkoutTimeout -> 0, connectionCustomizerClassName -> null, connectionTesterClassName -> com.mchange.v2.c3p0.impl.DefaultConnectionTester, contextClassLoaderSource -> caller, dataSourceName -> z8kfsxa41ni1p7ixqoy6p|73c13acd, debugUnreturnedConnectionStackTraces -> false, description -> null, driverClass -> org.hsqldb.jdbcDriver, extensions -> {}, factoryClassLocation -> null, forceIgnoreUnresolvedTransactions -> false, forceSynchronousCheckins -> false, forceUseNamedDriverClass -> false, identityToken -> z8kfsxa41ni1p7ixqoy6p|73c13acd, idleConnectionTestPeriod -> 0, initialPoolSize -> 3, jdbcUrl -> jdbc:hsqldb:mem:test?shutdown=true, maxAdministrativeTaskTime -> 0, maxConnectionAge -> 0, maxIdleTime -> 0, maxIdleTimeExcessConnections -> 0, maxPoolSize -> 15, maxStatements -> 0, maxStatementsPerConnection -> 0, minPoolSize -> 3, numHelperThreads -> 3, preferredTestQuery -> null, privilegeSpawnedThreads -> false, properties -> {}, propertyCycle -> 0, statementCacheNumDeferredCloseThreads -> 0, testConnectionOnCheckin -> false, testConnectionOnCheckout -> false, unreturnedConnectionTimeout -> 0, userOverrides -> {}, usesTraditionalReflectiveProxies -> false ]
Aug 28, 2019 12:18:32 PM io.vertx.core.impl.DeploymentManager
SEVERE: java.lang.NullPointerException
io.vertx.core.VertxException: java.lang.NullPointerException
	at io.vertx.ext.sync.Sync.awaitResult(Sync.java:50)
	at io.vertx.example.sync.jdbc.Client.start(Client.java:38)
	at io.vertx.ext.sync.SyncVerticle.lambda$start$72270b8a$1(SyncVerticle.java:26)
	at co.paralleluniverse.strands.SuspendableUtils$VoidSuspendableCallable.run(SuspendableUtils.java:44)
	at co.paralleluniverse.strands.SuspendableUtils$VoidSuspendableCallable.run(SuspendableUtils.java:32)
	at co.paralleluniverse.fibers.Fiber.run(Fiber.java:1097)
	at co.paralleluniverse.fibers.Fiber.run1(Fiber.java:1092)
	at co.paralleluniverse.fibers.Fiber.exec(Fiber.java:788)
	at co.paralleluniverse.fibers.RunnableFiberTask.doExec(RunnableFiberTask.java:100)
	at co.paralleluniverse.fibers.RunnableFiberTask.run(RunnableFiberTask.java:91)
	at io.vertx.ext.sync.Sync.lambda$getContextScheduler$2(Sync.java:202)
	at co.paralleluniverse.fibers.FiberExecutorScheduler.execute(FiberExecutorScheduler.java:85)
	at co.paralleluniverse.fibers.RunnableFiberTask.submit(RunnableFiberTask.java:296)
	at co.paralleluniverse.fibers.RunnableFiberTask.unpark(RunnableFiberTask.java:274)
	at co.paralleluniverse.fibers.Fiber.unpark(Fiber.java:1352)
	at co.paralleluniverse.fibers.FiberAsync.fire(FiberAsync.java:366)
	at co.paralleluniverse.fibers.FiberAsync.asyncCompleted(FiberAsync.java:328)
	at io.vertx.ext.sync.impl.AsyncAdaptor.handle(AsyncAdaptor.java:16)
	at io.vertx.ext.sync.impl.AsyncAdaptor.handle(AsyncAdaptor.java:11)
	at io.vertx.ext.jdbc.impl.JDBCClientImpl.lambda$null$8(JDBCClientImpl.java:295)
	at io.vertx.core.impl.ContextImpl.executeTask(ContextImpl.java:369)
	at io.vertx.core.impl.EventLoopContext.lambda$executeAsync$0(EventLoopContext.java:38)
	at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:163)
	at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:416)
	at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:515)
	at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:918)
	at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
	at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
	at java.base/java.lang.Thread.run(Thread.java:834)
Caused by: java.lang.NullPointerException
	at co.paralleluniverse.fibers.FiberAsync.run(FiberAsync.java:122)
	at io.vertx.ext.sync.Sync.awaitResult(Sync.java:48)
	... 28 more