Where do I declare my objects?

Question

I've never understood where to instantiate/construct/declare? my objects. For example when making a JFrame I could put
JFrame frame;
at the top of the program and the in the main class put
frame = new Frame();
or I could just put
JFrame frame = new JFrame();
Which one do I use and in what situation?

Answer 1

You could theoratically do both. Because it really depends on the scope of how you want to use your object.
For example, for the following code... You can subsequently use the xxx Object in xxxMethod2()....
public class NewClass {
     private Object xxx;
     public void xxxMethod() {
          xxx = new Object();
     public void xxxMethod2() {
}But for the following code... you can't use xxx in xxxMethod2()... since the scope of the object already ends in xxxMethod().
public class NewClass {
     public void xxxMethod() {
          Object xxx = new Object();
     public void xxxMethod2() {
}I hope i've made it simple enough for you to understand.