Import java.util.treemap;

Public class d

Public static void main(String[] args) {

ArrayList & lt string & gtlist = new ArrayList & lt string & gt ();

list . add(" a 1 b 1 c 1 ")；

list . add(" a2 B2 C2 ")；

Tree diagram & ltString, String & gt treemap = new treemap & lt string, string & gt ();

for(int I = 0； I< list. size (); i++){

treemap.put(list.get(i))。 split(" "[0]，list . get(I))；

}

}

}

//Put the string into the list in the Map, where a is the key.

//It's easier to put it in the list

ArrayList & lt string & gtnewList = new ArrayList & lt string & gt ();

new list . addall(treemap . values())；