Try to run this with Java 7 and Java 8 and see the difference (at least on Linux). EXPECTED VERSUS ACTUAL BEHAVIOR : EXPECTED - Each button color change should be visible as described. To do this add the following codes after/below the line - j Text Field1Text(""); j Text Field2Text(""); j Text Field3Text(""); j Text Field4Text(""); j Text Field5Text(""); j Text Field6Text(""); j Text Field7Text(""); JOption Message Dialog(null, "Table LIBRARY Updated! 6 On Delete button's 7 Here also I have used a JOption Pane to show a message to the user that the row was successfully deleted."); You can see that when a user clicks the update button the text-fields becomes empty and a message pops-ups stating that the table was updated successfully! Like the above message, you can also use various ways to make your program effective, example when a user clicks on delete button all the text fields gets cleared and also you can refresh the list to show that the deleted row does not exist any more in the database.
The Observer and Observable are defined in Java SE's package.This class starts the application; displays the two GUI windows. The example code Example App is listed at the end of this post.This is informed of changes in a Observable object (and, can receive notifications from multiple Observable objects).This has only one method, method receives these notifications and optional data.Useful methods in this class: add Observer(), remove Observer(), notify Observers(), set Changed() and has Changed().