import java.io.*;

(....)

private void jButton1MouseClicked(java.awt.event.MouseEvent evt) {
	// TODO add your handling code here:
	final JFileChooser fc = new JFileChooser();
	int returnVal = fc.showOpenDialog(jTextArea1);

	if(returnVal == 0) {
		String lesen;
		jLabel1.setText("file: " + fc.getName(fc.getSelectedFile()));

		try{
			// new file reader
			in = new BufferedReader(new FileReader(fc.getSelectedFile()));
			while((lesen=in.readLine())!=null) {
				jTextArea1.append(lesen+"\r\n");
			}
			in.close(); // closing file
			}
			catch(Exception ex1) {
				System.out.println(ex1);
			}
	}
	else {
		jTextArea1.setText("abort");
	}
}