Resume code after catching exception

Question 1

I got it working by adding a try block on the

conn = DriverManager.getConnection(url, username, password);

on the first method. it looks like this:

try {
  conn = DriverManager.getConnection(url, username, password);
  reachable = TestDB(conn);
} catch (Exception e) {
   reachable = false;
}

It is because the error is not with the second method. the error is the declaration of the connection.

Question 2

Could it just be that it's DriverManager.getConnection that throws the exception. Because as the code is written now, you only catch the exception thrown by conn.isClosed().

Question 3

because before your try catch block ,there is a Exception happening, and ,the try catch block can catch no Expcetion at all,may be u want to catch the code inner while loop, as the method getConnection alwayse throw an Exception if u give the wrong url、port、username or password

Question 4

I agree with peter Lawrey.and did you try to run in debug mode and checked what exaclty happening in TestDB method?

Can you also use stacktrace in your catch block and share the full stack trace here.

BTW are you handeling exception in first method, the method to which while loop belong?

Question 5

First of all correct your if condition

if (conn ==null || conn.isClosed())

By this

if (conn !=null && conn.isClosed())

Your if statement may throw error if it is null at conn.isClosed()

However you have catch exception and try with return; instead of return false; and you can put your stackTrace so exact error may identify.

Question 6

Have you tried removing Throws Exception ?

change

public boolean TestDB(Connection conn) throws Exception{

to

public boolean TestDB(Connection conn){

Question 7

you can use this statement, instead of the many lines you wrote.

try{
    return !conn.isClosed(); //true if open
}catch(Exception e){
    return false; //is false if nullPointerException is thrown (that mean conn is null)
}

This will simplify the code. At the end I think you should use a big try-catch that contains all the code, so everything is exception checked

while ((reachable == false) && (cnt <= 2)) {
        serverName = FPRODDB[cnt][0];
        sid = FPRODDB[cnt][1];
        url = "jdbc:oracle:thin:@" + serverName + ":" + portNumber + ":" + sid;
    try{
        conn = DriverManager.getConnection(url, username, password);
        reachable = TestDB(conn);
        JOptionPane.showMessageDialog(null,
        "Testing Connection: " + String.valueOf(cnt) ); 
        cnt ++;
    }catch(Exception e){
        // tell the user, or handle it
    }
    }