我不知道在哪里可以找到这个代码中错误的来源，希望有人能帮忙。本质上，这一小部分是我的一个更大的项目的一部分，创建一个计算器的图形用户界面。

JPanel box=new JPanel(); 
box.setPreferredSize(new Dimension(600,300)); 
BoxLayout b=new BoxLayout(box, BoxLayout.X_AXIS); 
box.setLayout(b); 
box.add(graphOutline); 
box.add(checks); 
box.add(checkd); 
box.add(check2d); 
box.add(radBut); 
box.add(yEquals);   
box.add(y); //}} //}}
//{{Bottom Buttons //{{ basicbuttons JPanel, includes all the numbers and decimal 

JPanel basicbuttons=new JPanel(); 
GridBagLayout gbl=new GridBagLayout(); 
GridBagConstraints c=new GridBagConstraints(); 

basicbuttons.setLayout(gbl); 

c.fill=GridBagConstraints.BOTH; //{{button 1 

JButton one = new JButton("1");     
one.setPreferredSize(new Dimension(60,40)); 

c.gridx=0; 
c.gridy=2; 
gbl.setConstraints(one, c); 

basicbuttons.add(one); //}} //{{button 2 

JButton two = new JButton("2"); 
two.setPreferredSize(new Dimension(60,40)); 

c.gridx=1; 
c.gridy=2; 
gbl.setConstraints(two, c); 

basicbuttons.add(two); //}} //{{button 3 

JButton three = new JButton("3"); 
three.setPreferredSize(new Dimension(60,40)); 

c.gridx=2; 
c.gridy=2; 
gbl.setConstraints(three, c); 

basicbuttons.add(three); //}} //{{button 4 

JButton four = new JButton("4"); 
four.setPreferredSize(new Dimension(60,40)); 

c.gridx=0; 
c.gridy=1; 
gbl.setConstraints(four, c); 

basicbuttons.add(four); //}} //{{button 5 

JButton five = new JButton("5"); 
one.setPreferredSize(new Dimension(60,40)); 

c.gridx=1; 
c.gridy=1; 
gbl.setConstraints(five, c);

basicbuttons.add(five); //}} //{{button 6 

JButton six = new JButton("6"); 
six.setPreferredSize(new Dimension(60,40)); 

c.gridx=2; 
c.gridy=1; 
gbl.setConstraints(six, c); 

basicbuttons.add(six); //}} //{{button 7 

JButton seven = new JButton("7"); 
seven.setPreferredSize(new Dimension(60,40)); 

c.gridx=0; c.gridy=0; 
gbl.setConstraints(seven, c); 

basicbuttons.add(seven); //}} //{{button 8 

JButton eight = new JButton("8"); 
eight.setPreferredSize(new Dimension(60,40)); 

c.gridx=1; 
c.gridy=0; 
gbl.setConstraints(eight, c); 

basicbuttons.add(eight); //}} //{{button 9  

JButton nine = new JButton("9"); 
nine.setPreferredSize(new Dimension(60,40)); 

c.gridx=2;  
c.gridy=0; 
gbl.setConstraints(nine, c); 

basicbuttons.add(nine); //}} //{{button 0

然而，我不断收到错误，例如
内标识“setPreferredSize”语法错误，此内标识后应为=
以及
标记“fill”出现语法错误，此标记后面需要VariableDeclaratorId
每当我尝试使用

box.setPreferredSize(new Dimension(600,300));

以及

c.fill=GridBagConstraints.BOTH;

分别。