[8u] RFR 8062947: Fix exception message to correctly represent LDAP connection failure

[Zhengyu Gu]

I would like to backport this patch to 8u for parity with Oracle 8u271.

The original patch applies cleanly on top of JDK-8151678, both are the 
followups of JDK-8160768.

However,  included new test uses new language feature 'var' which does 
not exist in 8u, fixed as follow:

diff -r 9c90228fb2d9 -r 96d71ec83814 
test/com/sun/jndi/ldap/NamingExceptionMessageTest.java
--- a/test/com/sun/jndi/ldap/NamingExceptionMessageTest.java	Thu May 07 
19:18:22 2020 +0100
+++ b/test/com/sun/jndi/ldap/NamingExceptionMessageTest.java	Mon Jul 13 
15:46:57 2020 -0400
@@ -51,11 +51,11 @@

      @Test
      public void timeoutMessageTest() throws Exception {
-        try (var ldapServer = TestLdapServer.newInstance(false)) {
+        try (TestLdapServer ldapServer = 
TestLdapServer.newInstance(false)) {
              ldapServer.start();
              ldapServer.awaitStartup();
-            var env = 
ldapServer.getInitialLdapCtxEnvironment(TIMEOUT_VALUE);
-            var namingException = 
Assert.expectThrows(NamingException.class, () -> new 
InitialDirContext(env));
+            Hashtable<Object, Object> env = 
ldapServer.getInitialLdapCtxEnvironment(TIMEOUT_VALUE);
+            Exception namingException = 
Assert.expectThrows(NamingException.class, () -> new 
InitialDirContext(env));
              System.out.println("Got naming exception:" + namingException);
              Assert.assertEquals(namingException.getMessage(), 
EXPECTED_TIMEOUT_MESSAGE);
          }
@@ -63,11 +63,11 @@

      @Test
      public void connectionClosureMessageTest() throws Exception {
-        try (var ldapServer = TestLdapServer.newInstance(true)) {
+        try (TestLdapServer ldapServer = 
TestLdapServer.newInstance(true)) {
              ldapServer.start();
              ldapServer.awaitStartup();
-            var env = ldapServer.getInitialLdapCtxEnvironment(0);
-            var namingException = 
Assert.expectThrows(NamingException.class, () -> new 
InitialDirContext(env));
+            Hashtable<Object, Object> env = 
ldapServer.getInitialLdapCtxEnvironment(0);
+            Exception namingException = 
Assert.expectThrows(NamingException.class, () -> new 
InitialDirContext(env));
              System.out.println("Got naming exception:" + namingException);
              Assert.assertEquals(namingException.getMessage(), 
EXPECTED_CLOSURE_MESSAGE);
          }


The original bug: https://bugs.openjdk.java.net/browse/JDK-8062947
The original patch: https://hg.openjdk.java.net/jdk/jdk/rev/868fe697bad4


8u webrev: http://cr.openjdk.java.net/~zgu/JDK-8062947-8u/webrev.00/

Test:
   Included NamingExceptionMessageTest.java test on Linux x86_64

Thanks,

-Zhengyu