The possible values for type: SWT.HORIZONTAL, SWT.VERTICAL
SWT.HORIZONTAL: lays the controls in a single row
SWT.VERTICAL: lays the controls in a single column.

import org.eclipse.swt.SWT;
import org.eclipse.swt.layout.FillLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;
public class FillLayoutHorizontal {
public static void main(String[] args) {
Display display = new Display();
Shell shell = new Shell(display);
shell.setLayout(new FillLayout(SWT.HORIZONTAL));
new Button(shell, SWT.PUSH).setText("one");
new Button(shell, SWT.PUSH).setText("two");
new Button(shell, SWT.PUSH).setText("three");
shell.open();
while (!shell.isDisposed()) {
if (!display.readAndDispatch()) {
display.sleep();
}
}
display.dispose();
}
}

import org.eclipse.swt.SWT;
import org.eclipse.swt.layout.FillLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;
public class FillLayoutVERTICAL {
public static void main(String[] args) {
Display display = new Display();
Shell shell = new Shell(display);
shell.setLayout(new FillLayout(SWT.VERTICAL));
new Button(shell, SWT.PUSH).setText("one");
new Button(shell, SWT.PUSH).setText("two");
new Button(shell, SWT.PUSH).setText("three");
shell.open();
while (!shell.isDisposed()) {
if (!display.readAndDispatch()) {
display.sleep();
}
}
display.dispose();
}
}