java - Create VolatileImage always return null -

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i creating volatile image in following class, hitting nullpointerexception every time. reason why createvolatileimage() returning null (from javadoc) graphicsenvironment.isheadless() true.

import java.awt.graphics; import java.awt.graphics2d; import java.awt.renderinghints; import java.awt.image.volatileimage; import javax.swing.jpanel;  public class tube extends jpanel {      private volatileimage image;     private int width, height;      public tube() {         super(true);     }      public tube(int width, int height) {         this.width = width;         this.height = height;         createimage();     }      @override     protected void paintcomponent(graphics g) {         super.paintcomponent(g);         if(image == null)             createimage();         if(image.validate(getgraphicsconfiguration()) == volatileimage.image_incompatible)             createimage();         graphics2d g2 = (graphics2d) g;         g2.setrenderinghint(renderinghints.key_antialiasing,                 renderinghints.value_antialias_on);         g2.setrenderinghint(renderinghints.key_text_antialiasing,                 renderinghints.value_text_antialias_lcd_hrgb);         g2.drawimage(image, 0, 0, this);     }      public volatileimage getbufferedimage() {         return this.image;     }      private void createimage(){         if(image != null){             image.flush();             image = null;         }         image = createvolatileimage(width, height);         image.setaccelerationpriority(1.0f);     } }

how can return non-null volatileimage ??

this change headless mode:

system.setproperty("java.awt.headless", "false");

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