讓arraylist等於另一個arraylist java

Question

我有1d臨時arraylist和2d原始數組列表，我更新了臨時arraylist在一個循環中，並在循環結束時，我需要使原始arraylist等於臨時內容數組列表如下：

while(!Front.get(front).isEmpty()){ 
     Q.clear(); 
     for(int i=0;i<Front.get(front).size();i++){ 
      if(!Individual_Dominate.get(Front.get(front).get(i)).isEmpty()){ 
       for(int j=0;j<Individual_Dominate.get(Front.get(front).get(i)).size();j++){ 
        Individual_Number[Individual_Dominate.get(Front.get(front).get(i)).get(j)]=Individual_Number[Individual_Dominate.get(Front.get(front).get(i)).get(j)]-1; 
        if(Individual_Number[Individual_Dominate.get(Front.get(front).get(i)).get(j)]==0){ 
         Solutions_to_arrange[Individual_Dominate.get(Front.get(front).get(i)).get(j)][Input.General_Inputs.Num_objectives+Input.General_Inputs.Num_Of_Ppes]=front+1; 
         Q.add(Individual_Dominate.get(Front.get(front).get(i)).get(j)); 
        } 
       } 
      } 
     } 
     front++; 
     Front.get(front)=Q // How to do this step 
    } 

我知道有像

Front.get(front) = new ArrayList<Object>(Q); 

或

Front.get(front) = (ArrayList<Object>)Q.clone(); 

方法

但不確定這些方法是否合適，因爲所有這些方法都會給我一個List的副本，而不是所有的元素。因此，如果我更改了我的複製列表中的某個元素，它也會在我的原始列表中更改。

更新 我提出這個解決方案的任何評論？

front++; 
for(int i=0;i<Q.size();i++) 
     Front.get(front).add(Q.get(i)); 
    } 

Answer 1

我認爲這會工作

while(!Front.get(front).isEmpty()){ 
     Q.clear(); 
     for(int i=0;i<Front.get(front).size();i++){ 
      if(!Individual_Dominate.get(Front.get(front).get(i)).isEmpty()){ 
       for(int j=0;j<Individual_Dominate.get(Front.get(front).get(i)).size();j++){ 
        Individual_Number[Individual_Dominate.get(Front.get(front).get(i)).get(j)]=Individual_Number[Individual_Dominate.get(Front.get(front).get(i)).get(j)]-1; 
        if(Individual_Number[Individual_Dominate.get(Front.get(front).get(i)).get(j)]==0){ 
         Solutions_to_arrange[Individual_Dominate.get(Front.get(front).get(i)).get(j)][Input.General_Inputs.Num_objectives+Input.General_Inputs.Num_Of_Ppes]=front+1; 
         Q.add(Individual_Dominate.get(Front.get(front).get(i)).get(j)); 
        } 
       } 
      } 
     } 
    front++; 
     for(int i=0;i<Q.size();i++) 
     Front.get(front).add(Q.get(i)); 
    }