Merge branch '2.3.x' of github.com-brettwooldridge:brettwooldridge/HikariCP into 2.3.x

# By Brett Wooldridge (1) and johnon (1)
* '2.3.x' of github.com-brettwooldridge:brettwooldridge/HikariCP:
  Fix #269 Guard against drivers that construct an SQLException where the 'cause' is self-referential.  Hopefully the cycle is not multi-layers deep, because this check will only guard against one "loop".
  Allows Hikari to look up an arbitary JNDI resource name for the metric registry

hikaricp-common/src/main/java/com/zaxxer/hikari/AbstractHikariConfig.java

@@ -26,7 +26,6 @@ import java.util.TreeSet;
 import java.util.concurrent.ThreadFactory;
 import java.util.concurrent.TimeUnit;
 
-import javax.naming.Context;
 import javax.naming.InitialContext;
 import javax.naming.NamingException;
 import javax.sql.DataSource;
@@ -505,8 +504,7 @@ public abstract class AbstractHikariConfig implements HikariConfigMBean
          if (metricRegistry instanceof String) {
             try {
                InitialContext initCtx = new InitialContext();
-               Context envCtx = (Context) initCtx.lookup("java:comp/env");
-               metricRegistry = (MetricRegistry) envCtx.lookup((String) metricRegistry);
+               metricRegistry = (MetricRegistry) initCtx.lookup((String) metricRegistry);
             }
             catch (NamingException e) {
                throw new IllegalArgumentException(e);
@@ -542,8 +540,7 @@ public abstract class AbstractHikariConfig implements HikariConfigMBean
          if (healthCheckRegistry instanceof String) {
             try {
                InitialContext initCtx = new InitialContext();
-               Context envCtx = (Context) initCtx.lookup("java:comp/env");
-               healthCheckRegistry = (MetricRegistry) envCtx.lookup((String) healthCheckRegistry);
+               healthCheckRegistry = (MetricRegistry) initCtx.lookup((String) healthCheckRegistry);
             }
             catch (NamingException e) {
                throw new IllegalArgumentException(e);

hikaricp-common/src/main/java/com/zaxxer/hikari/proxy/ConnectionProxy.java

@@ -109,7 +109,7 @@ public abstract class ConnectionProxy implements IHikariConnectionProxy
             LOGGER.warn(String.format("Connection %s (%s) marked as broken because of SQLSTATE(%s), ErrorCode(%d).", delegate.toString(),
                                       parentPool.toString(), sqlState, sqle.getErrorCode()), sqle);
          }
-         else if (sqle.getNextException() instanceof SQLException) {
+         else if (sqle.getNextException() instanceof SQLException && sqle != sqle.getNextException()) {
             checkException(sqle.getNextException());
          }
       }