What is the difference using addcomponents?

createAddButton();
addComponent(addButton);

public void createAddButton(){

addButton.addStyleName("default");
addButton.addListener(new Button.ClickListener() {

public void buttonClick(ClickEvent event) {

}
});

}

Style2

addComponent(createAddButton());

public Button createAddButton(){

addButton.addStyleName("default");
addButton.addListener(new Button.ClickListener() {

public void buttonClick(ClickEvent event) {

}
});

return addButton;
}