get string size
import java.awt.Font;
import java.awt.font.FontRenderContext;
import java.awt.geom.AffineTransform;
...
String text = "Hello World";
AffineTransform affinetransform = new AffineTransform();
FontRenderContext frc = new FontRenderContext(affinetransform,true,true);
Font font = new Font("Tahoma", Font.PLAIN, 12);
int textwidth = (int)(font.getStringBounds(text, frc).getWidth());
int textheight = (int)(font.getStringBounds(text, frc).getHeight());