how to handle nested exception in java?

Question

I am trying to connect to mysql database. I am using try catch while establishing connection. I want that I should be able to know what exception was caught, so that, I can show appropriate error message. e.g if I pass incorrect hostname, i should show Wrong hostname provided. One way to do is get class name of runtime exception class. but nested exception is being thrown like this..

There was some error while establishing connection to the databasecom.mysql.jdbc.CommunicationsException: Communications link failure due to underlying exception: -- BEGIN NESTED EXCEPTION -- java.net.UnknownHostException MESSAGE: localhsost STACKTRACE: java.net.UnknownHostException: localhsost at java.net.Inet6AddressImpl.lookupAllHostAddr(Native Method) at java.net.InetAddress$1.lookupAllHostAddr(InetAddress.java:867) at java.net.InetAddress.getAddressFromNameService(InetAddress.java:1246) at java.net.InetAddress.getAllByName0(InetAddress.java:1197) at java.net.InetAddress.getAllByName(InetAddress.java:1128) at java.net.InetAddress.getAllByName(InetAddress.java:1064) at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:246) at com.mysql.jdbc.MysqlIO.(MysqlIO.java:271) at com.mysql.jdbc.Connection.createNewIO(Connection.java:2771) at com.mysql.jdbc.Connection.(Connection.java:1555) at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:285) at java.sql.DriverManager.getConnection(DriverManager.java:620) at java.sql.DriverManager.getConnection(DriverManager.java:222) at accessMySQL.accessMySQL.createConnection(accessMySQL.java:24) at test.main(test.java:16) -- END NESTED EXCEPTION -- Last packet sent to the server was 1 ms ago. Problem in establishing connection.

Now I would like to know that class name UnknownHostException, so I can setup a condition like

if(e.getClass().toString() == "UnknownHostException")  
System.out.println("Exception caught while connection to database. Hostname appears to be incorrect");

please help !! P.s that typo in hostname is deliberately there to generate exception

Perception · Accepted Answer · 2011-08-10 14:00:42Z

3

Try this:

if (e.getCause() instanceof UnknownHostException) {
    // ...
}

edited Aug 10, 2011 at 14:00

Perception

80.8k19 gold badges190 silver badges197 bronze badges

answered Aug 9, 2011 at 14:24

ddso

1,73112 silver badges15 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

how to handle nested exception in java?

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related