Prevent possible deadlock

[trask]

I ran into the deadlock below in our distro, but it could potentially affect other people.

I found various discussions of the underlying Java 8 bug, but this is probably the best reference: https://bugs.openjdk.java.net/browse/JDK-8030092, and a good note at the bottom why it's no longer an issue in Java 9+.

Found one Java-level deadlock:
=============================
"sender":
  waiting to lock monitor 0x00007f8c38005b18 (object 0x000000073e4a2f00, a org.apache.juli.ClassLoaderLogManager),
  which is held by "main"
"main":
  waiting to lock monitor 0x00007f8c38003c28 (object 0x000000073e986518, a java.lang.Class),
  which is held by "sender"

Java stack information for the threads listed above:
===================================================
"sender":
        at java.util.logging.LogManager.ensureLogManagerInitialized(LogManager.java:317)
        - waiting to lock <0x000000073e4a2f00> (a org.apache.juli.ClassLoaderLogManager)
        at java.util.logging.LogManager.getLogManager(LogManager.java:378)
        at java.util.logging.Logger.getPlatformLogger(Logger.java:572)
        at java.util.logging.LoggingProxyImpl.getLogger(LoggingProxyImpl.java:41)
        at sun.util.logging.LoggingSupport.getLogger(LoggingSupport.java:100)
        at sun.util.logging.PlatformLogger$JavaLoggerProxy.<init>(PlatformLogger.java:602)
        at sun.util.logging.PlatformLogger$JavaLoggerProxy.<init>(PlatformLogger.java:597)
        at sun.util.logging.PlatformLogger.<init>(PlatformLogger.java:239)
        at sun.util.logging.PlatformLogger.getLogger(PlatformLogger.java:198)
        - locked <0x000000073e986518> (a java.lang.Class for sun.util.logging.PlatformLogger)
        at jdk.internal.event.EventHelper.isLoggingSecurity(EventHelper.java:138)
        at sun.security.provider.X509Factory.commitEvent(X509Factory.java:766)
        at sun.security.provider.X509Factory.engineGenerateCertificate(X509Factory.java:108)
        at java.security.cert.CertificateFactory.generateCertificate(CertificateFactory.java:339)
        at sun.security.provider.JavaKeyStore.engineLoad(JavaKeyStore.java:763)
        - locked <0x000000073e8af628> (a java.util.Hashtable)
        at sun.security.provider.JavaKeyStore$JKS.engineLoad(JavaKeyStore.java:57)
        at sun.security.provider.KeyStoreDelegator.engineLoad(KeyStoreDelegator.java:224)
        at sun.security.provider.JavaKeyStore$DualFormatJKS.engineLoad(JavaKeyStore.java:71)
        at java.security.KeyStore.load(KeyStore.java:1445)
        at sun.security.ssl.TrustStoreManager$TrustAnchorManager.loadKeyStore(TrustStoreManager.java:365)
        at sun.security.ssl.TrustStoreManager$TrustAnchorManager.getTrustedCerts(TrustStoreManager.java:313)
        - locked <0x000000073e8832e8> (a sun.security.ssl.TrustStoreManager$TrustAnchorManager)
        at sun.security.ssl.TrustStoreManager.getTrustedCerts(TrustStoreManager.java:55)
        at sun.security.ssl.TrustManagerFactoryImpl.engineInit(TrustManagerFactoryImpl.java:49)
        at javax.net.ssl.TrustManagerFactory.init(TrustManagerFactory.java:250)
        at sun.security.ssl.SSLContextImpl.engineInit(SSLContextImpl.java:88)
        at javax.net.ssl.SSLContext.init(SSLContext.java:282)
        at io.netty.handler.ssl.JdkSslContext.<clinit>(JdkSslContext.java:75)
        at io.netty.handler.ssl.SslContext.newClientContextInternal(SslContext.java:824)
        at io.netty.handler.ssl.SslContextBuilder.build(SslContextBuilder.java:611)
        ...

"main":
        at sun.util.logging.PlatformLogger.redirectPlatformLoggers(PlatformLogger.java:209)
        - waiting to lock <0x000000073e986518> (a java.lang.Class for sun.util.logging.PlatformLogger)
        at java.util.logging.LogManager$3.run(LogManager.java:402)
        at java.util.logging.LogManager$3.run(LogManager.java:396)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.util.logging.LogManager.readPrimordialConfiguration(LogManager.java:396)
        - locked <0x000000073e4a2f00> (a org.apache.juli.ClassLoaderLogManager)
        at java.util.logging.LogManager.access$800(LogManager.java:145)
        at java.util.logging.LogManager$2.run(LogManager.java:345)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.util.logging.LogManager.ensureLogManagerInitialized(LogManager.java:338)
        - locked <0x000000073e4a2f00> (a org.apache.juli.ClassLoaderLogManager)
        at java.util.logging.LogManager.getLogManager(LogManager.java:378)
        at java.util.logging.Logger.demandLogger(Logger.java:448)
        at java.util.logging.Logger.getLogger(Logger.java:502)
        at org.apache.juli.logging.DirectJDKLog.<init>(DirectJDKLog.java:68)
        at org.apache.juli.logging.DirectJDKLog.getInstance(DirectJDKLog.java:188)
        at org.apache.juli.logging.LogFactory.getInstance(LogFactory.java:131)
        at org.apache.juli.logging.LogFactory.getInstance(LogFactory.java:155)
        at org.apache.juli.logging.LogFactory.getLog(LogFactory.java:210)
        at org.apache.catalina.startup.Bootstrap.<clinit>(Bootstrap.java:52)

Found 1 deadlock.