LDAP related memory leaks

[vladak]

Describe the bug
Since switching LDAP servers from ldap:// to ldaps:// Tomcat reports memory leak related to com.sun.jndi.ldap.Connection

15-Apr-2020 11:20:34.475 WARNING [localhost-startStop-3] org.apache.catalina.loader.WebappClassLoaderBase.clearReferencesThreads The web application [source] appears to have started a thread named [Thread-439985
] but has failed to stop it. This is very likely to create a memory leak. Stack trace of thread:
 java.net.SocketInputStream.socketRead0(Native Method)
 java.net.SocketInputStream.socketRead(SocketInputStream.java:116)
 java.net.SocketInputStream.read(SocketInputStream.java:171)
 java.net.SocketInputStream.read(SocketInputStream.java:141)
 sun.security.ssl.InputRecord.readFully(InputRecord.java:465)
 sun.security.ssl.InputRecord.read(InputRecord.java:503)
 sun.security.ssl.SSLSocketImpl.readRecord(SSLSocketImpl.java:975)
 sun.security.ssl.SSLSocketImpl.readDataRecord(SSLSocketImpl.java:933)
 sun.security.ssl.AppInputStream.read(AppInputStream.java:105)
 java.io.BufferedInputStream.fill(BufferedInputStream.java:246)
 java.io.BufferedInputStream.read1(BufferedInputStream.java:286)
 java.io.BufferedInputStream.read(BufferedInputStream.java:345)
 com.sun.jndi.ldap.Connection.run(Connection.java:846)
 java.lang.Thread.run(Thread.java:748)

To Reproduce
Configure LDAP servers using ldaps:// in the LDAP setup for Ldap authorization plugins.

[vladak]

The LdapServer class uses https://docs.oracle.com/javase/7/docs/api/javax/naming/ldap/InitialLdapContext.html

Seems like threads are created to handle the connection to LDAP server. I found https://community.oracle.com/thread/732106 that mentions close() should be done to clean up the threads.

[vladak]

Looking into the source of jdk8/jdk/src/share/classes/com/sun/jndi/ldap/Connection.java there is indeed thread created and started in the Connection constructor however I don't see any code therein to terminate the thread.