Write User Input To Text File

I need to write a program where the user inputs name, age, email, and cell and write the user inputs to a text file. I need to have it so the file can be added to if more than one set of information is added. Currently, every time I click the button, the file is overwritten instead of added to. How do I correct this? Current code is as follows:

try
{
FileWriter writer = new FileWriter("ContactInformation.txt");
BufferedWriter bw = new BufferedWriter(writer);
nameTextField.write(bw);
bw.newLine();
ageTextField.write(bw);
bw.newLine();
emailTextField.write(bw);
bw.newLine();
cellTextField.write(bw);
bw.newLine();
bw.close();
nameTextField.setText("");
ageTextField.setText("");
emailTextField.setText("");
cellTextField.setText("");
nameTextField.requestFocus();
}