This question can be solved using all java libraries, no user made libraries imported are allowed:

Use Java to implement a simplified editing tool which allows the users to draw a directed graph with nodes and edges in the following way:

a node can be inserted, moved and deleted;

an edge can be inserted and deleted, but it cannot be moved.

You should guarantee that

any edge the users draw must connect two nodes;

when a node is moved, all its associated edges should be moved automatically;

when a node is deleted, all its associated edges should be deleted automatically.

The users should be allowed to save a graph to a file and open it again. Apart from the normal selections via menus, lists, buttons etc., the user can also use popup menus for the operations. A popup menu should be sensitive to its context, i.e., the GUI component on which it is triggered. Whenever necessary, users should be prompted with instructions on how to continue or what is wrong.

No rush, thank you to those who help