access object method from another class

access object method from another class

I'm new to Java and oriented-object and I'm trying to create a chat
program. Here's what I'm trying to do:
Somewhere in my Main.java
Window window = new Window;
Somewhere in my Window.java
History history = new History()
Somewhere in my History.java:
public History()
{
super(new GridBagLayout());
historyArea = new JTextArea(15, 40);
historyArea.setEditable(false);
JScrollPane scrollPane = new JScrollPane(historyArea);
entryArea = new JTextField(20);
entryArea.addActionListener(this);
GridBagConstraints gbc = new GridBagConstraints();
gbc.gridwidth = GridBagConstraints.REMAINDER;
gbc.fill = GridBagConstraints.HORIZONTAL;
add(scrollPane, gbc);
gbc.fill = GridBagConstraints.BOTH;
gbc.weightx = 1.0;
gbc.weighty = 1.0;
add(entryArea, gbc);
}
public void actionPerformed(ActionEvent event)
{
String text = entryArea.getText();
historyArea.append(text + newline);
entryArea.selectAll();
historyArea.setCaretPosition(historyArea.getDocument().getLength());
}
public JTextArea getHistoryArea()
{
return historyArea;
}
public void addToHistoryArea(String pStringToAdd)
{
historyArea.append(pStringToAdd + newline);
historyArea.setCaretPosition(historyArea.getDocument().getLength());
}
Now that I'm in Server.java, I want to use the method addToHistoryArea.
How can I do that without making my historyArea static? Because if I
understand well how static works, I couldn't have different historyArea
even if I create a new History...
Thanks for your help and tell me if I got it all wrong!