SWT Java Tutorial

import org.eclipse.swt.SWT;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Text;
public class LayoutDataControlLayout {
  public static void main(String[] args) {
    Display display = new Display();
    final Shell shell = new Shell(display);
    shell.setLayout(new GridLayout()); // Only with GridLayout you can use GridData
    Text text = new Text(shell, SWT.SINGLE|SWT.BORDER);
    text.setLayoutData(new GridData(GridData.GRAB_HORIZONTAL));
    
    shell.setSize(450, 100);
    shell.open();
    while (!shell.isDisposed()) {
      if (!display.readAndDispatch()) {
        display.sleep();
      }
    }
    display.dispose();
  }
}
The methods in the Control class to get and set layout data are:

public Object getLayoutData()
    public void setLayoutData(Object layoutData)