Could not find or load main Class on JAR executing

Question

I finished my project (in NetBeans) and i export Jar file (i set my main class in project properties correctly before exporting Jar):<

Answer 1

So,here comes an error to the problem---why have you mentioned con = DriverManager.getConnection(...); in your code?

And hence your code is catching SQL Exception!!! This is the source of error :-

public boolean userEnterCondition(char[] pass) {
Connection con;
PreparedStatement preparedStatement;
ResultSet resultSet;
String query = "Select * from users";
String password = null;
try {
    Class.forName("com.mysql.jdbc.Driver");
    con = DriverManager.getConnection(...);     //error in this line

................. and so on.

Replace it with

con =DriverManager.getConnection("jdbc:mysql://localhost/Library?" +
                               "user=yourusername&password=yourpassword");

I hope this helps.If still getting error,please comment below!

Answer 2

Open your jar file with WinRAR or a similar program. Then go to the META-INF folder and open the MANIFEST.MF. Make sure the property "Main-Class: your.class.path" is correct.