The following test timed out in the JDK16 CI:

com/sun/jndi/ldap/LdapDnsProviderTest.java

Here's a snippet from the log file:

#section:main
----------messages:(7/397)----------
command: main LdapDnsProviderTest
reason: User specified action: run main/othervm LdapDnsProviderTest
Mode: othervm [/othervm specified]
Additional options from @modules: --add-modules java.naming,java.base --add-exports java.naming/com.sun.jndi.ldap=ALL-UNNAMED --add-exports java.base/sun.net=ALL-UNNAMED
Timeout information:
--- Timeout information end.
elapsed time (seconds): 505.279
----------configuration:(5/177)----------
Boot Layer
  add modules: java.naming java.base
  add exports: java.base/sun.net ALL-UNNAMED
               java.naming/com.sun.jndi.ldap ALL-UNNAMED

----------System.out:(2/76)----------
Seed from RandomFactory = -1087174496408385825L
Timeout refired 480 times
----------System.err:(73/5073)*----------
TEST_CLASSES:
T:\\testoutput\\test-support\\jtreg_open_test_jdk_tier2_part2\\classes\\0\\com\\sun\\jndi\\ldap\\LdapDnsProviderTest.d
Testing: ldap:///dc=example,dc=com, localhost:389
javax.naming.CommunicationException: localhost:389 [Root exception is java.net.ConnectException: Connection refused: connect]
at java.naming/com.sun.jndi.ldap.Connection.<init>(Connection.java:237)
at java.naming/com.sun.jndi.ldap.LdapClient.<init>(LdapClient.java:137)
at java.naming/com.sun.jndi.ldap.LdapClient.getInstance(LdapClient.java:1610)
at java.naming/com.sun.jndi.ldap.LdapCtx.connect(LdapCtx.java:2751)
at java.naming/com.sun.jndi.ldap.LdapCtx.<init>(LdapCtx.java:319)
at java.naming/com.sun.jndi.ldap.LdapCtxFactory.getLdapCtxFromUrl(LdapCtxFactory.java:225)
at java.naming/com.sun.jndi.ldap.LdapCtxFactory.getUsingURL(LdapCtxFactory.java:189)
at java.naming/com.sun.jndi.ldap.LdapCtxFactory.getUsingURLs(LdapCtxFactory.java:243)
at java.naming/com.sun.jndi.ldap.LdapCtxFactory.getLdapCtxInstance(LdapCtxFactory.java:154)
at java.naming/com.sun.jndi.ldap.LdapCtxFactory.getInitialContext(LdapCtxFactory.java:84)
at java.naming/javax.naming.spi.NamingManager.getInitialContext(NamingManager.java:719)
at java.naming/javax.naming.InitialContext.getDefaultInitCtx(InitialContext.java:305)
at java.naming/javax.naming.InitialContext.init(InitialContext.java:236)
at java.naming/javax.naming.InitialContext.<init>(InitialContext.java:208)
at java.naming/javax.naming.directory.InitialDirContext.<init>(InitialDirContext.java:130)
at ProviderTest.call(LdapDnsProviderTest.java:115)
at ProviderTest.call(LdapDnsProviderTest.java:85)
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
at java.base/java.lang.Thread.run(Thread.java:832)
Caused by: java.net.ConnectException: Connection refused: connect
at java.base/sun.nio.ch.Net.connect0(Native Method)
at java.base/sun.nio.ch.Net.connect(Net.java:574)
at java.base/sun.nio.ch.Net.connect(Net.java:563)
at java.base/sun.nio.ch.NioSocketImpl.connect(NioSocketImpl.java:588)
at java.base/java.net.SocksSocketImpl.connect(SocksSocketImpl.java:333)
at java.base/java.net.Socket.connect(Socket.java:648)
at java.base/java.net.Socket.connect(Socket.java:597)
at java.base/java.net.Socket.<init>(Socket.java:520)
at java.base/java.net.Socket.<init>(Socket.java:294)
at java.naming/com.sun.jndi.ldap.Connection.createSocket(Connection.java:330)
at java.naming/com.sun.jndi.ldap.Connection.<init>(Connection.java:216)
... 18 more
Test passed
Testing: ldap://localhost/dc=example,dc=com, localhost:389
javax.naming.CommunicationException: localhost:389 [Root exception is java.net.ConnectException: Connection refused: connect]
at java.naming/com.sun.jndi.ldap.Connection.<init>(Connection.java:237)
at java.naming/com.sun.jndi.ldap.LdapClient.<init>(LdapClient.java:137)
at java.naming/com.sun.jndi.ldap.LdapClient.getInstance(LdapClient.java:1610)
at java.naming/com.sun.jndi.ldap.LdapCtx.connect(LdapCtx.java:2751)
at java.naming/com.sun.jndi.ldap.LdapCtx.<init>(LdapCtx.java:319)
at java.naming/com.sun.jndi.ldap.LdapCtxFactory.getLdapCtxFromUrl(LdapCtxFactory.java:225)
at java.naming/com.sun.jndi.ldap.LdapCtxFactory.getUsingURL(LdapCtxFactory.java:189)
at java.naming/com.sun.jndi.ldap.LdapCtxFactory.getUsingURLs(LdapCtxFactory.java:243)
at java.naming/com.sun.jndi.ldap.LdapCtxFactory.getLdapCtxInstance(LdapCtxFactory.java:154)
at java.naming/com.sun.jndi.ldap.LdapCtxFactory.getInitialContext(LdapCtxFactory.java:84)
at java.naming/javax.naming.spi.NamingManager.getInitialContext(NamingManager.java:719)
at java.naming/javax.naming.InitialContext.getDefaultInitCtx(InitialContext.java:305)
at java.naming/javax.naming.InitialContext.init(InitialContext.java:236)
at java.naming/javax.naming.InitialContext.<init>(InitialContext.java:208)
at java.naming/javax.naming.directory.InitialDirContext.<init>(InitialDirContext.java:130)
at ProviderTest.call(LdapDnsProviderTest.java:115)
at ProviderTest.call(LdapDnsProviderTest.java:85)
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
at java.base/java.lang.Thread.run(Thread.java:832)
Caused by: java.net.ConnectException: Connection refused: connect
at java.base/sun.nio.ch.Net.connect0(Native Method)
at java.base/sun.nio.ch.Net.connect(Net.java:574)
at java.base/sun.nio.ch.Net.connect(Net.java:563)
at java.base/sun.nio.ch.NioSocketImpl.connect(NioSocketImpl.java:588)
at java.base/java.net.SocksSocketImpl.connect(SocksSocketImpl.java:333)
at java.base/java.net.Socket.connect(Socket.java:648)
at java.base/java.net.Socket.connect(Socket.java:597)
at java.base/java.net.Socket.<init>(Socket.java:520)
at java.base/java.net.Socket.<init>(Socket.java:294)
at java.naming/com.sun.jndi.ldap.Connection.createSocket(Connection.java:330)
at java.naming/com.sun.jndi.ldap.Connection.<init>(Connection.java:216)
... 18 more
Test passed
Iteration 0: Testing: ldap://localhost:1538/dc=example,dc=com, localhost:1538
----------rerun:(45/5285)*----------

Don't be fooled by the two
"ConnectException: Connection refused: connect"
since both of those exceptions appear to be expected
by the sub-tests. When both exception occurred, the
sub-test reported "Test passed"