Prevent SQL injection attacks in a Java program

I have to add a statement to my java program to update a database table:

String insert =
    "INSERT INTO customer(name,address,email) VALUES('" + name + "','" + addre + "','" + email + "');";

I heard that this can be exploited through an SQL injection like:

DROP TABLE customer; 

My program has a Java GUI and all name, address and email values are retrieved from Jtextfields. I want to know how the following code (DROP TABLE customer;) could be added to my insert statement by a hacker and how I can prevent this.