java - fusion of images without using of buffereimage -

i merge many images one, instantiate bufferedimage :

for (int i=0;i<listimagetmp.size();i++) {        if (listimagetmp.get(i)!=null) {         image src = listimagetmp.get(i);                 bufferedimage bimage = new bufferedimage(src.getwidth(null), src.getheight(null), bufferedimage.type_int_rgb);              // draw image on buffered image             graphics2d bgr = bimage.creategraphics();             bgr.drawimage(src, 0, 0, null);             bgr.dispose();             int[] pixels = ((databufferint) bimage.getraster().getdatabuffer()).getdata();             for(int x =0; x<bimage.getwidth();x++){                 for(int y =0; y<bimage.getheight();y++){                     int newrgbvalue = pixels[y * bimage.getwidth() + x];                     int oldvalue = bufferedimage.getrgb(x, y);                     if((newrgbvalue > oldvalue) && (oldvalue != -16777216) && (newrgbvalue == 16777215)){                         newrgbvalue = oldvalue;                     }                     bufferedimage.setrgb(x, y, newrgbvalue);                 }             }      } }  node = new pimage(bufferedimage); bufferedimage.flush(); bufferedimage.getgraphics().dispose(); bufferedimage = null; pimage node2 =  (pimage) node.clone();     // clonage node = null; getcanvas().getlayer().addchild(node2); 

and have heap space memory error. need know: how can fix it?