Java merging arrays and show them on the panel

I have initialized a java panel and several checkboxes. And when I click two or three checkboxes and the panel will display the combination of selected array of checkboxes. like:

{ {1，2，3}, {3，4，5} }
{ {1，1}， {2，2} }

after merging:

A：{ {1，2，3}， {1，2}， {3，4，5}， {1，1}， {2，2} }

and actually I want to know how to merge arrays which are more than two.And show them on the panel.