com.sun.jndi.ldap.Connection#cleanup does not close underlying socket if the is an IOException generation in the below code.
 
This causes ldap connection build ups that get cleared only during GC.
 
This also causes issues with Ldap SSL Handshakes and causes additional delay . Even after the connection is abandoned by the Ldap client the connection is not closed. Ldap server assumes the server is active and keeps reattempting to complete the handshake for the timeout period (currently set to 300s ) .
 
com.sun.jndi.ldap.Connection#cleanup

void cleanup(Control[] reqCtls, boolean notifyParent) {
660 boolean nparent = false;
 
676 } finally {
677 try {
678 outStream.flush(); // try to perform a flush - that triggers a socket readtimeout .
679 sock.close(); // socket close is not called.
680 unpauseReader();
681 } catch (IOException ie) {
682 if (debug)
683 System.err.println("Connection: problem closing socket: " + ie);
684 }
 
 
Stack Triggering the timeout.
 
 at sun.security.ssl.SSLSocketImpl.access$200(java.base/SSLSocketImpl.java:76)
 at sun.security.ssl.SSLSocketImpl$AppOutputStream.write(java.base/SSLSocketImpl.java:1138)
 at java.io.BufferedOutputStream.flushBuffer(java.base/BufferedOutputStream.java:82)
 at java.io.BufferedOutputStream.flush(java.base/BufferedOutputStream.java:140)
        - locked <0x00000007dd63ea80> (a java.io.BufferedOutputStream)
 at com.sun.jndi.ldap.Connection.cleanup(java.base/Connection.java:678)
        - locked <0x00000007dd63ea98> (a com.sun.jndi.ldap.Connection)
 at com.sun.jndi.ldap.Connection.writeRequest(java.base/Connection.java:453)
 at com.sun.jndi.ldap.Connection.writeRequest(java.base/Connection.java:423)
 at com.sun.jndi.ldap.LdapClient.ldapBind(java.base/LdapClient.java:359)
        - locked <0x00000007dd63eb88> (a com.sun.jndi.ldap.LdapClient)
 at com.sun.jndi.ldap.LdapClient.authenticate(java.base/LdapClient.java:214)
        - locked <0x00000007dd63eb88> (a com.sun.jndi.ldap.LdapClient)
 at com.sun.jndi.ldap.LdapCtx.connect(java.base/LdapCtx.java:2895)
        - locked <0x00000007dd63ebc0> (a java.lang.Object)
 at com.sun.jndi.ldap.LdapCtx.<init>(java.base/LdapCtx.java:348)
 
 
 jdk.JavaExceptionThrow {
  startTime = 19:21:23.192
  message = "Read timed out"
  thrownClass = java.net.SocketTimeoutException (classLoader = bootstrap)
  eventThread = "[STUCK] ExecuteThread: '239' for queue:
'weblogic.kernel.Default (self-tuning)'" (javaThreadId
  stackTrace = [
    java.lang.Throwable.<init>(String) line: 275
    java.lang.Exception.<init>(String) line: 66
    java.io.IOException.<init>(String) line: 58
    java.io.InterruptedIOException.<init>(String) line: 64
    java.net.SocketTimeoutException.<init>(String) line: 43
    java.net.SocketInputStream.socketRead0(FileDescriptor, byte[], int, int, int)
    java.net.SocketInputStream.socketRead(FileDescriptor, byte[], int, int, int) line: 116
    java.net.SocketInputStream.read(byte[], int, int, int) line: 171
    java.net.SocketInputStream.read(byte[], int, int) line: 141
    sun.security.ssl.SSLSocketInputRecord.read(InputStream, byte[], int, int) line: 475
    sun.security.ssl.SSLSocketInputRecord.readHeader() line: 469
    sun.security.ssl.SSLSocketInputRecord.decode(ByteBuffer[], int, int) line: 159
    sun.security.ssl.SSLTransport.decode(TransportContext, ByteBuffer[], int, int, ByteBuffer[], int, int) line
    sun.security.ssl.SSLSocketImpl.decode(ByteBuffer) line: 1320
    sun.security.ssl.SSLSocketImpl.readHandshakeRecord() line: 1233
    sun.security.ssl.SSLSocketImpl.startHandshake(boolean) line: 417
    sun.security.ssl.SSLSocketImpl.ensureNegotiated(boolean) line: 837
    sun.security.ssl.SSLSocketImpl.access$200(SSLSocketImpl, boolean) line: 76
    sun.security.ssl.SSLSocketImpl$AppOutputStream.write(byte[], int, int) line: 1138
    java.io.BufferedOutputStream.flushBuffer() line: 82
    java.io.BufferedOutputStream.flush() line: 140
    com.sun.jndi.ldap.Connection.cleanup(Control[], boolean) line: 678
    com.sun.jndi.ldap.Connection.writeRequest(BerEncoder, int, boolean, int) line: 453
    com.sun.jndi.ldap.Connection.writeRequest(BerEncoder, int, boolean) line: 423
    com.sun.jndi.ldap.LdapClient.ldapBind(String, byte[], Control[], String, boolean) line: 359
    com.sun.jndi.ldap.LdapClient.authenticate(boolean, String, Object, int, String, Control[], Hashtable) line:
    com.sun.jndi.ldap.LdapCtx.connect(boolean) line: 2895
    com.sun.jndi.ldap.LdapCtx.<init>(String, String, int, Hashtable, boolean) line: 348
    com.sun.jndi.ldap.LdapCtxFactory.getLdapCtxFromUrl(String, String, LdapURL, Hashtable) line: 225
    com.sun.jndi.ldap.LdapCtxFactory.getUsingURL(String, Hashtable) line: 189
    com.sun.jndi.ldap.LdapCtxFactory.getUsingURLs(String[], Hashtable) line: 243
    com.sun.jndi.ldap.LdapCtxFactory.getLdapCtxInstance(Object, Hashtable) line: 154
    com.sun.jndi.ldap.LdapCtxFactory.getInitialContext(Hashtable) line: 84
    javax.naming.spi.NamingManager.getInitialContext(Hashtable) line: 694
    javax.naming.InitialContext.getDefaultInitCtx() line: 313
    javax.naming.InitialContext.init(Hashtable) line: 244
    javax.naming.ldap.InitialLdapContext.<init>(Hashtable, Control[]) line: 154